Fix build warning at mxser.c introduced by 
dfc7b837c7f9 (tty: mxser: fix
usage of opmode_ioaddr)
Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
                return mxser_ioctl_special(cmd, argp);
 
        if (cmd == MOXA_SET_OP_MODE || cmd == MOXA_GET_OP_MODE) {
-               if (info->board->chip_flag != MOXA_MUST_MU860_HWID)
-                       return -EFAULT;
-
                int p;
                unsigned long opmode;
                static unsigned char ModeMask[] = { 0xfc, 0xf3, 0xcf, 0x3f };
                int shiftbit;
                unsigned char val, mask;
 
+               if (info->board->chip_flag != MOXA_MUST_MU860_HWID)
+                       return -EFAULT;
+
                p = tty->index % 4;
                if (cmd == MOXA_SET_OP_MODE) {
                        if (get_user(opmode, (int __user *) argp))