drm/mxsfb: 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 mxsfb 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
v3:
- fix driver name "msxfb" to "mxsfb"

Signed-off-by: Thomas Zimmermann <[e-mail]>
Cc: Marek Vasut <[e-mail]>
Cc: Stefan Agner <[e-mail]>
Cc: Shawn Guo <[e-mail]>
Cc: Sascha Hauer <[e-mail]>
Cc: Pengutronix Kernel Team <[e-mail]>
Cc: Fabio Estevam <[e-mail]>
Acked-by: Javier Martinez Canillas <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/mxsfb/Kconfig

···
 	depends on DRM && OF
 	depends on COMMON_CLK
 	depends on ARCH_MXS || ARCH_MXC || COMPILE_TEST
+	select DRM_CLIENT_SELECTION
 	select DRM_MXS
 	select DRM_KMS_HELPER
 	select DRM_GEM_DMA_HELPER

drivers/gpu/drm/mxsfb/mxsfb_drv.c

···
 
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
+#include <drm/drm_client_setup.h>
 #include <drm/drm_connector.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_fbdev_dma.h>
···
 static const struct drm_driver mxsfb_driver = {
 	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
 	DRM_GEM_DMA_DRIVER_OPS,
+	DRM_FBDEV_DMA_DRIVER_OPS,
 	.fops	= &fops,
 	.name	= "mxsfb-drm",
 	.desc	= "MXSFB Controller DRM",
···
 	if (ret)
 		goto err_unload;
 
-	drm_fbdev_dma_setup(drm, 32);
+	drm_client_setup(drm, NULL);
 
 	return 0;