btrfs: Remove unused parameter from check_direct_IO

Introduced by 5a5f79b57069 ("Btrfs: allow unaligned DIO") and never
used. The buffered fallback from unaligned DIO works as expected.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Timofey Titovets <nefelim4ag@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/inode.c

@@ -8786,7 +8786,6 @@ free_ordered:
 }
 
 static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
-			       struct kiocb *iocb,
 			       const struct iov_iter *iter, loff_t offset)
 {
 	int seg;
@@ -8833,7 +8832,7 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 	bool relock = false;
 	ssize_t ret;
 
-	if (check_direct_IO(fs_info, iocb, iter, offset))
+	if (check_direct_IO(fs_info, iter, offset))
 		return 0;
 
 	inode_dio_begin(inode);