zink: move zink_batch_state::db_bound reset to zink_batch_descriptor_reset()

descriptor code goes in descriptor file

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21246>

src/gallium/drivers/zink/zink_batch.c

@@ -155,7 +155,6 @@ zink_reset_batch_state(struct zink_context *ctx, struct zink_batch_state *bs)
     */
    bs->fence.submitted = false;
    bs->has_barriers = false;
-   bs->db_bound = false;
    if (bs->fence.batch_id)
       zink_screen_update_last_finished(screen, bs->fence.batch_id);
    bs->submit_count++;

src/gallium/drivers/zink/zink_descriptors.c

@@ -1449,6 +1449,7 @@ zink_batch_descriptor_reset(struct zink_screen *screen, struct zink_batch_state
 {
    if (zink_descriptor_mode == ZINK_DESCRIPTOR_MODE_DB) {
       bs->dd.db_offset = 0;
+      bs->db_bound = false;
    } else {
       for (unsigned i = 0; i < ZINK_DESCRIPTOR_BASE_TYPES; i++) {
          struct zink_descriptor_pool_multi **mpools = bs->dd.pools[i].data;