video: lcd: Remove useless BACKLIGHT_CLASS_DEVICE dependencies

This patch removes dependencies on BACKLIGHT_CLASS_DEVICE for items
that are already placed under 'if BACKLIGHT_CLASS_DEVICE'.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>