drm: panel/simple: add backlight dependency

The simple panel code uses the backlight interface to
find a device, which fails when backlight is disabled:

drivers/built-in.o: In function `panel_simple_platform_probe':
:(.text+0xd3c48): undefined reference to `of_find_backlight_by_node'

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Dave Airlie <airlied@gmail.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 84506053a7ca..d84583776d50 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -10,6 +10,7 @@ menu "Display Panels"
 config DRM_PANEL_SIMPLE
         tristate "support for simple panels"
         depends on OF
+        depends on BACKLIGHT_CLASS_DEVICE
         help
           DRM panel driver for dumb panels that need at most a regulator and
           a GPIO to be powered up. Optionally a backlight can be attached so