drm/gma500: Use regular fbdev I/O helpers

Use the regular fbdev helpers for framebuffer I/O instead of DRM's
helpers. Gma500 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: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230530151228.22979-6-tzimmermann@suse.de

drivers/gpu/drm/gma500/Kconfig

@@ -3,6 +3,7 @@ config DRM_GMA500
 	tristate "Intel GMA500/600/3600/3650 KMS Framebuffer"
 	depends on DRM && PCI && X86 && MMU
 	select DRM_KMS_HELPER
+	select FB_IO_HELPERS if DRM_FBDEV_EMULATION
 	select I2C
 	select I2C_ALGOBIT
 	# GMA500 depends on ACPI_VIDEO when ACPI is enabled, just like i915

drivers/gpu/drm/gma500/fbdev.c

@@ -5,6 +5,7 @@
  *
  **************************************************************************/
 
+#include <linux/fb.h>
 #include <linux/pfn_t.h>
 
 #include <drm/drm_crtc_helper.h>
@@ -134,13 +135,10 @@ static void psb_fbdev_fb_destroy(struct fb_info *info)
 
 static const struct fb_ops psb_fbdev_fb_ops = {
 	.owner = THIS_MODULE,
+	__FB_DEFAULT_IO_OPS_RDWR,
 	DRM_FB_HELPER_DEFAULT_OPS,
 	.fb_setcolreg = psb_fbdev_fb_setcolreg,
-	.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_DRAW,
 	.fb_mmap = psb_fbdev_fb_mmap,
 	.fb_destroy = psb_fbdev_fb_destroy,
 };