CIFS: Remove extra mutex_unlock in cifs_lock_add_if

to prevent the mutex being unlocked twice if we interrupt a blocked lock.
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/file.c

@@ -778,7 +778,6 @@ cifs_lock_add_if(struct cifsInodeInfo *cinode, __u64 offset, __u64 length,
 		else {
 			mutex_lock(&cinode->lock_mutex);
 			list_del_init(&lock->blist);
-			mutex_unlock(&cinode->lock_mutex);
 		}
 	}