drm/loongson: 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.

The loongson driver specifies a preferred color mode of 32. As this
is the default if no format has been given, leave it out entirely.

v5:
- select DRM_CLIENT_SELECTION

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Sui Jingfeng <suijingfeng@loongson.cn>
Acked-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Link: https://patchwork.freedesktop.org/patch/msgid/20240924071734.98201-68-tzimmermann@suse.de

Author: tdz

drivers/gpu/drm/loongson/Kconfig

@@ -4,6 +4,7 @@ config DRM_LOONGSON
 	tristate "DRM support for Loongson Graphics"
 	depends on DRM && PCI && MMU
 	depends on LOONGARCH || MIPS || COMPILE_TEST
+	select DRM_CLIENT_SELECTION
 	select DRM_KMS_HELPER
 	select DRM_TTM
 	select DRM_TTM_HELPER

drivers/gpu/drm/loongson/lsdc_drv.c

@@ -9,6 +9,7 @@
 #include <drm/drm_aperture.h>
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
+#include <drm/drm_client_setup.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_fbdev_ttm.h>
 #include <drm/drm_gem_framebuffer_helper.h>
@@ -47,6 +48,7 @@ static const struct drm_driver lsdc_drm_driver = {
 	.dumb_create = lsdc_dumb_create,
 	.dumb_map_offset = lsdc_dumb_map_offset,
 	.gem_prime_import_sg_table = lsdc_prime_import_sg_table,
+	DRM_FBDEV_TTM_DRIVER_OPS,
 };
 
 static const struct drm_mode_config_funcs lsdc_mode_config_funcs = {
@@ -314,7 +316,7 @@ static int lsdc_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (ret)
 		return ret;
 
-	drm_fbdev_ttm_setup(ddev, 32);
+	drm_client_setup(ddev, NULL);
 
 	return 0;
 }