drm/armada: Use regular fbdev I/O helpers

Use the regular fbdev helpers for framebuffer I/O instead of DRM's
helpers. Armada 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 <tzimmermann@suse.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Russell King <linux@armlinux.org.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20230530151228.22979-4-tzimmermann@suse.de

Author: tdz

drivers/gpu/drm/armada/Kconfig

@@ -3,6 +3,7 @@ config DRM_ARMADA
 	tristate "DRM support for Marvell Armada SoCs"
 	depends on DRM && HAVE_CLK && ARM && MMU
 	select DRM_KMS_HELPER
+	select FB_IO_HELPERS if DRM_FBDEV_EMULATION
 	help
 	  Support the "LCD" controllers found on the Marvell Armada 510
 	  devices.  There are two controllers on the device, each controller

drivers/gpu/drm/armada/armada_fbdev.c

@@ -5,6 +5,7 @@
  */
 
 #include <linux/errno.h>
+#include <linux/fb.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 
@@ -33,12 +34,8 @@ static void armada_fbdev_fb_destroy(struct fb_info *info)
 
 static const struct fb_ops armada_fb_ops = {
 	.owner		= THIS_MODULE,
+	FB_DEFAULT_IO_OPS,
 	DRM_FB_HELPER_DEFAULT_OPS,
-	.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	= armada_fbdev_fb_destroy,
 };