fbdev/gxt4500: 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 <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Helge Deller <deller@gmx.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230803184034.6456-19-tzimmermann@suse.de

drivers/video/fbdev/Kconfig

@@ -1752,9 +1752,7 @@ config FB_UDL
 config FB_IBM_GXT4500
 	tristate "Framebuffer support for IBM GXT4000P/4500P/6000P/6500P adaptors"
 	depends on FB
-	select FB_CFB_FILLRECT
-	select FB_CFB_COPYAREA
-	select FB_CFB_IMAGEBLIT
+	select FB_IOMEM_HELPERS
 	select VIDEO_NOMODESET
 	help
 	  Say Y here to enable support for the IBM GXT4000P/6000P and

drivers/video/fbdev/gxt4500.c

@@ -602,14 +602,12 @@ static const struct fb_fix_screeninfo gxt4500_fix = {
 
 static const struct fb_ops gxt4500_ops = {
 	.owner = THIS_MODULE,
+	FB_DEFAULT_IOMEM_OPS,
 	.fb_check_var = gxt4500_check_var,
 	.fb_set_par = gxt4500_set_par,
 	.fb_setcolreg = gxt4500_setcolreg,
 	.fb_pan_display = gxt4500_pan_display,
 	.fb_blank = gxt4500_blank,
-	.fb_fillrect = cfb_fillrect,
-	.fb_copyarea = cfb_copyarea,
-	.fb_imageblit = cfb_imageblit,
 };
 
 /* PCI functions */