fbdev/geode/gxfb: 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]>
Cc: Andres Salomon <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/video/fbdev/geode/Kconfig

···
 config FB_GEODE_GX
 	tristate "AMD Geode GX framebuffer support"
 	depends on FB && FB_GEODE
-	select FB_CFB_FILLRECT
-	select FB_CFB_COPYAREA
-	select FB_CFB_IMAGEBLIT
+	select FB_IOMEM_HELPERS
 	select VIDEO_NOMODESET
 	help
 	  Framebuffer driver for the display controller integrated into the

drivers/video/fbdev/geode/gxfb_core.c

···
 
 static const struct fb_ops gxfb_ops = {
 	.owner		= THIS_MODULE,
+	FB_DEFAULT_IOMEM_OPS,
 	.fb_check_var	= gxfb_check_var,
 	.fb_set_par	= gxfb_set_par,
 	.fb_setcolreg	= gxfb_setcolreg,
 	.fb_blank       = gxfb_blank,
-	/* No HW acceleration for now. */
-	.fb_fillrect	= cfb_fillrect,
-	.fb_copyarea	= cfb_copyarea,
-	.fb_imageblit	= cfb_imageblit,
 };
 
 static struct fb_info *gxfb_init_fbinfo(struct device *dev)