drm/exynos: enable OF_VIDEOMODE and FB_MODE_HELPERS for exynos drm fimd

patch adds "select OF_VIDEOMODE" and "select FB_MODE_HELPERS" when
EXYNOS_DRM_FIMD config is selected. Also adds the "OF" dependency.
Signed-off-by: Vikas Sajjan <vikas.sajjan@linaro.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/Kconfig

@@ -24,7 +24,9 @@ config DRM_EXYNOS_DMABUF
 
 config DRM_EXYNOS_FIMD
 	bool "Exynos DRM FIMD"
-	depends on DRM_EXYNOS && !FB_S3C && !ARCH_MULTIPLATFORM
+	depends on OF && DRM_EXYNOS && !FB_S3C && !ARCH_MULTIPLATFORM
+	select OF_VIDEOMODE
+	select FB_MODE_HELPERS
 	help
 	  Choose this option if you want to use Exynos FIMD for DRM.