btrfs: drop the -EBUSY case in __extent_writepage_io

Now that we only return 0 or -EAGAIN from btrfs_writepage_cow_fixup, we
do not need this -EBUSY case.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent_io.c

@@ -3442,11 +3442,7 @@ static noinline_for_stack int __extent_writepage_io(struct inode *inode,
 	ret = btrfs_writepage_cow_fixup(page, start, page_end);
 	if (ret) {
 		/* Fixup worker will requeue */
-		if (ret == -EBUSY)
-			wbc->pages_skipped++;
-		else
 		redirty_page_for_writepage(wbc, page);
-
 		update_nr_written(wbc, nr_written);
 		unlock_page(page);
 		return 1;