fbdev: ssd1307fb: Remove struct backlight_ops.check_fb

The driver sets struct fb_info.bl_dev to the correct backlight
device. Thus rely on the backlight core code to match backlight
and framebuffer devices, and remove the extra check_fb function
from struct backlight_ops.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20240305162425.23845-10-tzimmermann@suse.de


Signed-off-by: Lee Jones <lee@kernel.org>