pipe-loader: Default to kmsro if probe fails

A device supported by kmsro will not automatically probe kmsro since the
driver name will be panfrost/lima/v3d/..., not "kmsro". Since kmsro is a
bit of a catch-all for generic (mostly embedded) GPUs, add a fallback on
kmsro for the dynamic loader.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Acked-by: Karol Herbst <kherbst@redhat.com>

src/gallium/auxiliary/pipe-loader/pipe_loader_drm.c

@@ -208,6 +208,11 @@ pipe_loader_drm_probe_fd_nodup(struct pipe_loader_device **dev, int fd)
    plib = &ddev->lib;
 #endif
    ddev->dd = get_driver_descriptor(ddev->base.driver_name, plib);
+
+   /* kmsro supports lots of drivers, try as a fallback */
+   if (!ddev->dd)
+      ddev->dd = get_driver_descriptor("kmsro", plib);
+
    if (!ddev->dd)
       goto fail;