md: fix semicolon.cocci warnings

drivers/md/md.c:7175:43-44: Unneeded semicolon

 Removes unneeded semicolon.

Generated by: scripts/coccinelle/misc/semicolon.cocci
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>

drivers/md/md.c

@@ -6969,7 +6969,7 @@ static unsigned int mdstat_poll(struct file *filp, poll_table *wait)
 	int mask;
 
 	if (md_unloading)
-		return POLLIN|POLLRDNORM|POLLERR|POLLPRI;;
+		return POLLIN|POLLRDNORM|POLLERR|POLLPRI;
 	poll_wait(filp, &md_event_waiters, wait);
 
 	/* always allow read */