bcachefs: Remove dead code in __build_ro_aux_tree

This logic is no longer useful since commit
3ce8b463 ("bcachefs: kill bset_tree->max_key"), so remove it.
Signed-off-by: Alan Huang <mmpgouride@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/bset.c

@@ -753,9 +753,6 @@ static noinline void __build_ro_aux_tree(struct btree *b, struct bset_tree *t)
 		EBUG_ON(tree_to_bkey(b, t, j) != k);
 	}
 
-	while (k != btree_bkey_last(b, t))
-		prev = k, k = bkey_p_next(k);
-
 	if (!bkey_pack_pos(bkey_to_packed(&min_key), b->data->min_key, b)) {
 		bkey_init(&min_key.k);
 		min_key.k.p = b->data->min_key;