drm: rcar-du: Drop LVDS double dependency on OF

LVDS support depends on DRM_RCAR_DU which already depends on OF. Drop
the explicit dependency.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

drivers/gpu/drm/rcar-du/Kconfig

@@ -15,7 +15,6 @@ config DRM_RCAR_DU
 config DRM_RCAR_HDMI
 	bool "R-Car DU HDMI Encoder Support"
 	depends on DRM_RCAR_DU
-	depends on OF
 	help
 	  Enable support for external HDMI encoders.