fs/stat.c: avoid harmless garbage value problem in vfs_statx_path()

fs/stat.c: avoid harmless garbage value problem in vfs_statx_path()

Clang static checker(scan-build) warning:
fs/stat.c:287:21: warning: The left expression of the compound assignment is
an uninitialized value. The computed value will also be garbage.
  287 |                 stat->result_mask |= STATX_MNT_ID_UNIQUE;
      |                 ~~~~~~~~~~~~~~~~~ ^
fs/stat.c:290:21: warning: The left expression of the compound assignment is
an uninitialized value. The computed value will also be garbage.
  290 |                 stat->result_mask |= STATX_MNT_ID;

When vfs_getattr() failed because of security_inode_getattr(), 'stat' is
uninitialized. In this case, there is a harmless garbage problem in
vfs_statx_path(). It's better to return error directly when
vfs_getattr() failed, avoiding garbage value and more clearly.

Signed-off-by: Su Hui <suhui@nfschina.com>
Link: https://lore.kernel.org/r/20250119025946.1168957-1-suhui@nfschina.com
Signed-off-by: Christian Brauner <brauner@kernel.org>