drm/st7735r: 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: David Lechner <[e-mail]>
Acked-by: David Lechner <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/tiny/Kconfig

···
 config TINYDRM_ST7735R
 	tristate "DRM support for Sitronix ST7715R/ST7735R display panels"
 	depends on DRM && SPI
+	select DRM_CLIENT_SELECTION
 	select DRM_KMS_HELPER
 	select DRM_GEM_DMA_HELPER
 	select DRM_MIPI_DBI

drivers/gpu/drm/tiny/st7735r.c

···
 #include <video/mipi_display.h>
 
 #include <drm/drm_atomic_helper.h>
+#include <drm/drm_client_setup.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_fbdev_dma.h>
 #include <drm/drm_gem_atomic_helper.h>
···
 	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
 	.fops			= &st7735r_fops,
 	DRM_GEM_DMA_DRIVER_OPS_VMAP,
+	DRM_FBDEV_DMA_DRIVER_OPS,
 	.debugfs_init		= mipi_dbi_debugfs_init,
 	.name			= "st7735r",
 	.desc			= "Sitronix ST7735R",
···
 
 	spi_set_drvdata(spi, drm);
 
-	drm_fbdev_dma_setup(drm, 0);
+	drm_client_setup(drm, NULL);
 
 	return 0;
 }