drm/exynos: Use regular fbdev I/O helpers

Use the regular fbdev helpers for framebuffer I/O instead of DRM's
helpers. Exynos 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
v3:
* don't reorder Makefile rules (Sam)
v2:
* use FB_IO_HELPERS option

Signed-off-by: Thomas Zimmermann <[e-mail]>
Acked-by: Sam Ravnborg <[e-mail]>
Cc: Inki Dae <[e-mail]>
Cc: Seung-Woo Kim <[e-mail]>
Cc: Kyungmin Park <[e-mail]>
Cc: Krzysztof Kozlowski <[e-mail]>
Cc: Alim Akhtar <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/exynos/Kconfig

···
 	select DRM_DISPLAY_HELPER if DRM_EXYNOS_DP
 	select DRM_KMS_HELPER
 	select VIDEOMODE_HELPERS
+	select FB_IO_HELPERS if DRM_FBDEV_EMULATION
 	select SND_SOC_HDMI_CODEC if SND_SOC
 	help
 	  Choose this option if you have a Samsung SoC Exynos chipset.

drivers/gpu/drm/exynos/exynos_drm_fbdev.c

···
  *	Seung-Woo Kim <[e-mail]>
  */
 
+#include <linux/fb.h>
+
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_fb_helper.h>
···
 
 static const struct fb_ops exynos_drm_fb_ops = {
 	.owner		= THIS_MODULE,
+	__FB_DEFAULT_IO_OPS_RDWR,
 	DRM_FB_HELPER_DEFAULT_OPS,
+	__FB_DEFAULT_IO_OPS_DRAW,
 	.fb_mmap        = exynos_drm_fb_mmap,
-	.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_destroy	= exynos_drm_fb_destroy,
 };