src/mount_clear_sock.c: fix compiling error

src/mount_clear_sock.c: fix compiling error

<linux/mount.h> and <sys/mount.h> are known pairs of headers that conflict
See https://sourceware.org/glibc/wiki/Synchronizing_Headers
$ make
make -C src all
make[1]: Entering directory '/root/blktests/src'
cc  -O2 -Wall -Wshadow  -DHAVE_LINUX_BLKZONED_H -o mount_clear_sock mount_clear_sock.c
In file included from /usr/include/linux/fs.h:19,
                 from mount_clear_sock.c:15:
/usr/include/linux/mount.h:95:6: error: redeclaration of ‘enum fsconfig_command’
   95 | enum fsconfig_command {
      |      ^~~~~~~~~~~~~~~~
In file included from mount_clear_sock.c:11:
/usr/include/sys/mount.h:189:6: note: originally defined here
  189 | enum fsconfig_command
      |      ^~~~~~~~~~~~~~~~
/usr/include/linux/mount.h:96:9: error: redeclaration of enumerator ‘FSCONFIG_SET_FLAG’
   96 |         FSCONFIG_SET_FLAG       = 0,    /* Set parameter, supplying no value */
      |         ^~~~~~~~~~~~~~~~~
/usr/include/sys/mount.h:191:3: note: previous definition of ‘FSCONFIG_SET_FLAG’ with type ‘enum fsconfig_command’
  191 |   FSCONFIG_SET_FLAG       = 0,    /* Set parameter, supplying no value */
      |   ^~~~~~~~~~~~~~~~~
/usr/include/linux/mount.h:97:9: error: redeclaration of enumerator ‘FSCONFIG_SET_STRING’
   97 |         FSCONFIG_SET_STRING     = 1,    /* Set parameter, supplying a string value */
      |         ^~~~~~~~~~~~~~~~~~~
/usr/include/sys/mount.h:193:3: note: previous definition of ‘FSCONFIG_SET_STRING’ with type ‘enum fsconfig_command’
  193 |   FSCONFIG_SET_STRING     = 1,    /* Set parameter, supplying a string value */
      |   ^~~~~~~~~~~~~~~~~~~
/usr/include/linux/mount.h:98:9: error: redeclaration of enumerator ‘FSCONFIG_SET_BINARY’
   98 |         FSCONFIG_SET_BINARY     = 2,    /* Set parameter, supplying a binary blob value */
      |         ^~~~~~~~~~~~~~~~~~~
/usr/include/sys/mount.h:195:3: note: previous definition of ‘FSCONFIG_SET_BINARY’ with type ‘enum fsconfig_command’
  195 |   FSCONFIG_SET_BINARY     = 2,    /* Set parameter, supplying a binary blob value */
      |   ^~~~~~~~~~~~~~~~~~~
/usr/include/linux/mount.h:99:9: error: redeclaration of enumerator ‘FSCONFIG_SET_PATH’
   99 |         FSCONFIG_SET_PATH       = 3,    /* Set parameter, supplying an object by path */
      |         ^~~~~~~~~~~~~~~~~
/usr/include/sys/mount.h:197:3: note: previous definition of ‘FSCONFIG_SET_PATH’ with type ‘enum fsconfig_command’
  197 |   FSCONFIG_SET_PATH       = 3,    /* Set parameter, supplying an object by path */
      |   ^~~~~~~~~~~~~~~~~
/usr/include/linux/mount.h:100:9: error: redeclaration of enumerator ‘FSCONFIG_SET_PATH_EMPTY’
  100 |         FSCONFIG_SET_PATH_EMPTY = 4,    /* Set parameter, supplying an object by (empty) path */
      |         ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/sys/mount.h:199:3: note: previous definition of ‘FSCONFIG_SET_PATH_EMPTY’ with type ‘enum fsconfig_command’
  199 |   FSCONFIG_SET_PATH_EMPTY = 4,    /* Set parameter, supplying an object by (empty) path */
      |   ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/linux/mount.h:101:9: error: redeclaration of enumerator ‘FSCONFIG_SET_FD’
  101 |         FSCONFIG_SET_FD         = 5,    /* Set parameter, supplying an object by fd */
      |         ^~~~~~~~~~~~~~~
/usr/include/sys/mount.h:201:3: note: previous definition of ‘FSCONFIG_SET_FD’ with type ‘enum fsconfig_command’
  201 |   FSCONFIG_SET_FD         = 5,    /* Set parameter, supplying an object by fd */
      |   ^~~~~~~~~~~~~~~
/usr/include/linux/mount.h:102:9: error: redeclaration of enumerator ‘FSCONFIG_CMD_CREATE’
  102 |         FSCONFIG_CMD_CREATE     = 6,    /* Invoke superblock creation */
      |         ^~~~~~~~~~~~~~~~~~~
/usr/include/sys/mount.h:203:3: note: previous definition of ‘FSCONFIG_CMD_CREATE’ with type ‘enum fsconfig_command’
  203 |   FSCONFIG_CMD_CREATE     = 6,    /* Invoke superblock creation */
      |   ^~~~~~~~~~~~~~~~~~~
/usr/include/linux/mount.h:103:9: error: redeclaration of enumerator ‘FSCONFIG_CMD_RECONFIGURE’
  103 |         FSCONFIG_CMD_RECONFIGURE = 7,   /* Invoke superblock reconfiguration */
      |         ^~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/sys/mount.h:205:3: note: previous definition of ‘FSCONFIG_CMD_RECONFIGURE’ with type ‘enum fsconfig_command’
  205 |   FSCONFIG_CMD_RECONFIGURE = 7,   /* Invoke superblock reconfiguration */
      |   ^~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/linux/mount.h:129:8: error: redefinition of ‘struct mount_attr’
  129 | struct mount_attr {
      |        ^~~~~~~~~~
/usr/include/sys/mount.h:161:8: note: originally defined here
  161 | struct mount_attr
      |        ^~~~~~~~~~

Signed-off-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>