backlight: lcd: Replace check_fb with controls_device

Rename check_fb in struct lcd_ops to controls_device. The callback
is now independent from fbdev's struct fb_info and tests if an lcd
device controls a hardware display device. The new naming and semantics
follow similar functionality for backlight devices.

v2:
- fix typos in commit description (Daniel)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20240906075439.98476-27-tzimmermann@suse.de


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