fbdev/controlfb: Initialize fb_ops to fbdev I/O-memory helpers

Initialize the instance of struct fb_ops with fbdev initializer
macros for framebuffers in I/O address space. Set the read/write,
draw and mmap callbacks to the correct implementation and avoid
implicit defaults. Also select the necessary I/O helpers in Kconfig.

Fbdev drivers sometimes rely on the callbacks being NULL for a
default implementation to be invoked; hence requiring the I/O
helpers to be built in any case. Setting all callbacks in all
drivers explicitly will allow to make the I/O helpers optional.
This benefits systems that do not use these functions.

No functional changes.

Signed-off-by: Thomas Zimmermann <[e-mail]>
Acked-by: Javier Martinez Canillas <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/video/fbdev/Kconfig

···
 config FB_CONTROL
 	bool "Apple \"control\" display support"
 	depends on (FB = y) && ((PPC_PMAC && PPC32) || COMPILE_TEST)
-	select FB_CFB_FILLRECT
-	select FB_CFB_COPYAREA
-	select FB_CFB_IMAGEBLIT
+	select FB_IOMEM_HELPERS
 	select FB_MACMODES
 	help
 	  This driver supports a frame buffer for the graphics adapter in the

drivers/video/fbdev/controlfb.c

···
 
 static const struct fb_ops controlfb_ops = {
 	.owner		= THIS_MODULE,
+	__FB_DEFAULT_IOMEM_OPS_RDWR,
 	.fb_check_var	= controlfb_check_var,
 	.fb_set_par	= controlfb_set_par,
 	.fb_setcolreg	= controlfb_setcolreg,
 	.fb_pan_display = controlfb_pan_display,
 	.fb_blank	= controlfb_blank,
+	__FB_DEFAULT_IOMEM_OPS_DRAW,
 	.fb_mmap	= controlfb_mmap,
-	.fb_fillrect	= cfb_fillrect,
-	.fb_copyarea	= cfb_copyarea,
-	.fb_imageblit	= cfb_imageblit,
 };
 
 /*