fbdev/i810fb: 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 <tzimmermann@suse.de>
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230927074722.6197-20-tzimmermann@suse.de

drivers/video/fbdev/Kconfig

@@ -793,10 +793,8 @@ config FB_I740
 config FB_I810
 	tristate "Intel 810/815 support"
 	depends on FB && PCI && X86_32 && AGP_INTEL
+	select FB_IOMEM_FOPS
 	select FB_MODE_HELPERS
-	select FB_CFB_FILLRECT
-	select FB_CFB_COPYAREA
-	select FB_CFB_IMAGEBLIT
 	select VGASTATE
 	select VIDEO_NOMODESET
 	help

drivers/video/fbdev/i810/i810_main.c

@@ -1547,6 +1547,7 @@ static const struct fb_ops i810fb_ops = {
 	.owner =             THIS_MODULE,
 	.fb_open =           i810fb_open,
 	.fb_release =        i810fb_release,
+	__FB_DEFAULT_IOMEM_OPS_RDWR,
 	.fb_check_var =      i810fb_check_var,
 	.fb_set_par =        i810fb_set_par,
 	.fb_setcolreg =      i810fb_setcolreg,
@@ -1557,6 +1558,7 @@ static const struct fb_ops i810fb_ops = {
 	.fb_imageblit =      i810fb_imageblit,
 	.fb_cursor =         i810fb_cursor,
 	.fb_sync =           i810fb_sync,
+	__FB_DEFAULT_IOMEM_OPS_MMAP,
 };
 
 /***********************************************************************