auxdisplay/cfag12864bfb: Initialize fb_ops with fbdev macros

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

Fbdev drivers sometimes rely on the callbacks being NULL for a
default I/O-memory-based 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.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231127131655.4020-9-tzimmermann@suse.de

drivers/auxdisplay/Kconfig

@@ -112,10 +112,7 @@ config CFAG12864B
 	depends on X86
 	depends on FB
 	depends on KS0108
-	select FB_SYS_FILLRECT
-	select FB_SYS_COPYAREA
-	select FB_SYS_IMAGEBLIT
-	select FB_SYS_FOPS
+	select FB_SYSMEM_HELPERS
 	default n
 	help
 	  If you have a Crystalfontz 128x64 2-color LCD, cfag12864b Series,

drivers/auxdisplay/cfag12864bfb.c

@@ -56,11 +56,8 @@ static int cfag12864bfb_mmap(struct fb_info *info, struct vm_area_struct *vma)
 
 static const struct fb_ops cfag12864bfb_ops = {
 	.owner = THIS_MODULE,
-	.fb_read = fb_sys_read,
-	.fb_write = fb_sys_write,
-	.fb_fillrect = sys_fillrect,
-	.fb_copyarea = sys_copyarea,
-	.fb_imageblit = sys_imageblit,
+	__FB_DEFAULT_SYSMEM_OPS_RDWR,
+	__FB_DEFAULT_SYSMEM_OPS_DRAW,
 	.fb_mmap = cfag12864bfb_mmap,
 };