fbdev/acornfb: Use fbdev I/O helpers

Set struct fb_ops and with FB_DEFAULT_IOMEM_OPS, fbdev's initializer
for I/O memory. Sets the callbacks to the cfb_ and fb_io_ functions.
Select the correct modules with Kconfig's FB_IOMEM_HELPERS token.

The macro and token set the currently selected values, so there is
no functional change.

v3:
* use _IOMEM_ in commit message
v2:
* updated to use _IOMEM_ tokens

Signed-off-by: Thomas Zimmermann <[e-mail]>
Reviewed-by: Sam Ravnborg <[e-mail]>
Acked-by: Helge Deller <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/video/fbdev/Kconfig

···
 config FB_ACORN
 	bool "Acorn VIDC support"
 	depends on (FB = y) && ARM && ARCH_ACORN
-	select FB_CFB_FILLRECT
-	select FB_CFB_COPYAREA
-	select FB_CFB_IMAGEBLIT
+	select FB_IOMEM_HELPERS
 	help
 	  This is the frame buffer device driver for the Acorn VIDC graphics
 	  hardware found in Acorn RISC PCs and other ARM-based machines.  If

drivers/video/fbdev/acornfb.c

···
 
 static const struct fb_ops acornfb_ops = {
 	.owner		= THIS_MODULE,
+	FB_IOMEM_DEFAULT_OPS,
 	.fb_check_var	= acornfb_check_var,
 	.fb_set_par	= acornfb_set_par,
 	.fb_setcolreg	= acornfb_setcolreg,
 	.fb_pan_display	= acornfb_pan_display,
-	.fb_fillrect	= cfb_fillrect,
-	.fb_copyarea	= cfb_copyarea,
-	.fb_imageblit	= cfb_imageblit,
 };
 
 /*