The dependecies for BACKLIGHT_CLASS_DEVICE are defined a bit
strange, but it seems one has to always select both BACKLIGHT_CLASS_DEVICE
and BACKLIGHT_LCD_SUPPORT to avoid this error:
drivers/gpu/drm/tilcdc/tilcdc_panel.c:396:
undefined reference to `of_find_backlight_by_node'
Cc: Rob Clark <robdclark@gmail.com> Cc: dri-devel@lists.freedesktop.org Cc: Dave Airlie <airlied@redhat.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Dave Airlie <airlied@gmail.com>