fbdev: Add Kconfig options to select different fb_ops helpers

Many fbdev drivers use the same set of fb_ops helpers. Add Kconfig
options to select them at once. This will help with making DRM's
fbdev emulation code more modular, but can also be used to simplify
fbdev's driver configs.

v3:
	* fix select statement (Jingfeng)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sui Jingfeng <suijingfeng@loongson.cn>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230530151228.22979-2-tzimmermann@suse.de