bcachefs: lru, accounting are alloc btrees

They can be regenerated by fsck and don't require a btree node scan,
like other alloc btrees.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/bcachefs_format.h

@@ -1359,6 +1359,8 @@ static inline bool btree_id_is_alloc(enum btree_id id)
 	case BTREE_ID_need_discard:
 	case BTREE_ID_freespace:
 	case BTREE_ID_bucket_gens:
+	case BTREE_ID_lru:
+	case BTREE_ID_accounting:
 		return true;
 	default:
 		return false;