zink: simplify redundant is_buffer check

it's in the params

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24775>

src/gallium/drivers/zink/zink_resource.h

@@ -180,7 +180,7 @@ zink_batch_resource_usage_set(struct zink_batch *batch, struct zink_resource *re
          if (acquire)
             util_dynarray_append(&batch->state->acquires, VkSemaphore, acquire);
       }
-      if (write && !res->obj->is_buffer) {
+      if (write) {
          if (!res->valid && res->fb_bind_count)
             batch->state->ctx->rp_loadop_changed = true;
          res->valid = true;