etnaviv: always try to create KMS side handles for imported resources

By creating the KMS side handles we allow GBM to return the proper KMS
side GEM handles for imported buffers. Always creating the KMS side
handles adds a bit of overhead, as we don't need them on all imported
resources, but seems like the most robust solution for now.

Cc: mesa-stable
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12018>

src/gallium/drivers/etnaviv/etnaviv_resource.c

@@ -566,6 +566,16 @@ etna_resource_from_handle(struct pipe_screen *pscreen,
    if (!rsc->pending_ctx)
       goto fail;
 
+   if (screen->ro) {
+      struct pipe_resource *imp_prsc = prsc;
+      do {
+         etna_resource(imp_prsc)->scanout =
+               renderonly_create_gpu_import_for_resource(imp_prsc, screen->ro,
+                                                         NULL);
+         /* failure is expected for scanout incompatible buffers */
+      } while ((imp_prsc = imp_prsc->next));
+   }
+
    return prsc;
 
 fail: