backlight: Add controls_device callback to struct backlight_ops

backlight: Add controls_device callback to struct backlight_ops

Replace check_fb with controls_device in struct backlight_ops. The
new callback interface takes a Linux device instead of a framebuffer.
Resolves one of the dependencies of backlight.h on fb.h.

The few drivers that had custom implementations of check_fb can easily
use the framebuffer's Linux device instead. Update them accordingly.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20240305162425.23845-11-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>