bcachefs: kill btree_trans_too_many_iters() in bch2_bucket_alloc_freelist()

When we're called via
trans commit -> btree split -> allocator

We may have already arbitrarily many btree_paths, for the transaction
commit we're trying to do; when this happens, the
btree_trans_too_many_iters() call causes us to livelock.

Since the allocator calls btree_iter_dontneed to release paths as it
iterates, this shouldn't cause any problems.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/alloc_foreground.c

@@ -496,12 +496,6 @@ static struct open_bucket *bch2_bucket_alloc_freelist(struct btree_trans *trans,
 		for (alloc_cursor = max(alloc_cursor, bkey_start_offset(k.k));
 		     alloc_cursor < k.k->p.offset;
 		     alloc_cursor++) {
-			ret = btree_trans_too_many_iters(trans);
-			if (ret) {
-				ob = ERR_PTR(ret);
-				break;
-			}
-
 			s->buckets_seen++;
 
 			u64 bucket = alloc_cursor & ~(~0ULL << 56);