drm/rockchip: Run DRM default client setup

Call drm_client_setup() to run the kernel's default client setup
for DRM. Set fbdev_probe in struct drm_driver, so that the client
setup can start the common fbdev client.

v5:
- select DRM_CLIENT_SELECTION

Signed-off-by: Thomas Zimmermann <[e-mail]>
Cc: Sandy Huang <[e-mail]>
Cc: "Heiko Stübner" <[e-mail]>
Cc: Andy Yan <[e-mail]>
Acked-by: Heiko Stuebner <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/rockchip/Kconfig

···
 config DRM_ROCKCHIP
 	tristate "DRM Support for Rockchip"
 	depends on DRM && ROCKCHIP_IOMMU
+	select DRM_CLIENT_SELECTION
 	select DRM_GEM_DMA_HELPER
 	select DRM_KMS_HELPER
 	select DRM_PANEL

drivers/gpu/drm/rockchip/rockchip_drm_drv.c

···
 #include <linux/iommu.h>
 
 #include <drm/drm_aperture.h>
+#include <drm/drm_client_setup.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_fbdev_dma.h>
 #include <drm/drm_gem_dma_helper.h>
···
 	if (ret)
 		goto err_kms_helper_poll_fini;
 
-	drm_fbdev_dma_setup(drm_dev, 0);
+	drm_client_setup(drm_dev, NULL);
 
 	return 0;
 err_kms_helper_poll_fini:
···
 	.driver_features	= DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
 	.dumb_create		= rockchip_gem_dumb_create,
 	.gem_prime_import_sg_table	= rockchip_gem_prime_import_sg_table,
+	DRM_FBDEV_DMA_DRIVER_OPS,
 	.fops			= &rockchip_drm_driver_fops,
 	.name	= DRIVER_NAME,
 	.desc	= DRIVER_DESC,