drm/radeon: Use regular fbdev I/O helpers

Use the regular fbdev helpers for framebuffer I/O instead of DRM's
helpers. Radeon does not use damage handling, so DRM's fbdev helpers
are mere wrappers around the fbdev code.

By using fbdev helpers directly within each DRM fbdev emulation,
we can eventually remove DRM's wrapper functions entirely.

v4:
* use initializer macros for struct fb_ops
v2:
* use FB_IO_HELPERS option

Signed-off-by: Thomas Zimmermann <[e-mail]>
Acked-by: Alex Deucher <[e-mail]>
Acked-by: Sam Ravnborg <[e-mail]>
Cc: Alex Deucher <[e-mail]>
Cc: "Christian König" <[e-mail]>
Cc: "Pan, Xinhui" <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/radeon/Kconfig

···
 	select DRM_SUBALLOC_HELPER
         select DRM_TTM
 	select DRM_TTM_HELPER
+	select FB_IO_HELPERS if DRM_FBDEV_EMULATION
 	select SND_HDA_COMPONENT if SND_HDA_CORE
 	select POWER_SUPPLY
 	select HWMON

drivers/gpu/drm/radeon/radeon_fbdev.c

···
  *     David Airlie
  */
 
+#include <linux/fb.h>
 #include <linux/pci.h>
 #include <linux/pm_runtime.h>
 #include <linux/vga_switcheroo.h>
···
 
 static const struct fb_ops radeon_fbdev_fb_ops = {
 	.owner = THIS_MODULE,
-	DRM_FB_HELPER_DEFAULT_OPS,
 	.fb_open = radeon_fbdev_fb_open,
 	.fb_release = radeon_fbdev_fb_release,
-	.fb_read = drm_fb_helper_cfb_read,
-	.fb_write = drm_fb_helper_cfb_write,
-	.fb_fillrect = drm_fb_helper_cfb_fillrect,
-	.fb_copyarea = drm_fb_helper_cfb_copyarea,
-	.fb_imageblit = drm_fb_helper_cfb_imageblit,
+	FB_DEFAULT_IO_OPS,
+	DRM_FB_HELPER_DEFAULT_OPS,
 	.fb_destroy = radeon_fbdev_fb_destroy,
 };