drm/virtio: Use fbdev-shmem

Implement fbdev emulation with fbdev-shmem. Avoids the overhead of
fbdev-generic's additional shadow buffering. No functional changes.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Gurchetan Singh <gurchetansingh@chromium.org>
Cc: Chia-I Wu <olvaffe@gmail.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240419083331.7761-20-tzimmermann@suse.de

drivers/gpu/drm/virtio/virtgpu_drv.c

@@ -35,7 +35,7 @@
 #include <drm/drm_aperture.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_drv.h>
-#include <drm/drm_fbdev_generic.h>
+#include <drm/drm_fbdev_shmem.h>
 #include <drm/drm_file.h>
 
 #include "virtgpu_drv.h"
@@ -103,7 +103,7 @@ static int virtio_gpu_probe(struct virtio_device *vdev)
 	if (ret)
 		goto err_deinit;
 
-	drm_fbdev_generic_setup(vdev->priv, 32);
+	drm_fbdev_shmem_setup(vdev->priv, 32);
 	return 0;
 
 err_deinit: