auxdisplay/ht16k33: 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>
Cc: Robin van der Gracht <robin@protonic.nl>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Robin van der Gracht <robin@protonic.nl>
Link: https://patchwork.freedesktop.org/patch/msgid/20231127131655.4020-11-tzimmermann@suse.de

drivers/auxdisplay/Kconfig

@@ -167,10 +167,7 @@ config IMG_ASCII_LCD
 config HT16K33
 	tristate "Holtek Ht16K33 LED controller with keyscan"
 	depends on FB && I2C && INPUT
-	select FB_SYS_FOPS
-	select FB_SYS_FILLRECT
-	select FB_SYS_COPYAREA
-	select FB_SYS_IMAGEBLIT
+	select FB_SYSMEM_HELPERS
 	select INPUT_MATRIXKMAP
 	select FB_BACKLIGHT
 	select NEW_LEDS

drivers/auxdisplay/ht16k33.c

@@ -356,12 +356,9 @@ static int ht16k33_mmap(struct fb_info *info, struct vm_area_struct *vma)
 
 static const struct fb_ops ht16k33_fb_ops = {
 	.owner = THIS_MODULE,
-	.fb_read = fb_sys_read,
-	.fb_write = fb_sys_write,
+	__FB_DEFAULT_SYSMEM_OPS_RDWR,
 	.fb_blank = ht16k33_blank,
-	.fb_fillrect = sys_fillrect,
-	.fb_copyarea = sys_copyarea,
-	.fb_imageblit = sys_imageblit,
+	__FB_DEFAULT_SYSMEM_OPS_DRAW,
 	.fb_mmap = ht16k33_mmap,
 };