bcachefs: Fix missing error check in journal_entry_btree_keys_validate()

Closes: https://syzkaller.appspot.com/bug?extid=8996d8f176cf946ef641Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/journal_io.c

@@ -415,6 +415,8 @@ static int journal_entry_btree_keys_validate(struct bch_fs *c,
 					       flags|BCH_VALIDATE_journal);
 		if (ret == FSCK_DELETED_KEY)
 			continue;
+		else if (ret)
+			return ret;
 
 		k = bkey_next(k);
 	}