backlight: platform_lcd: Remove include statement for <linux/backlight.h>

This lcd driver does not depend on backlight interfaces. Remove the
include statement.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20240906075439.98476-17-tzimmermann@suse.de


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