drm/exynos: restore parallel output interface support

The patch adds parallel output interface to FIMD device driver.
It also restores support for panels initialized by boot loader,
but without proper kernel driver.
Driver uses video interface bindings to find connected panel.
It uses drm_panel interface to interact with the panel.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
diff --git a/drivers/gpu/drm/exynos/Kconfig b/drivers/gpu/drm/exynos/Kconfig
index 7eea698..56f9581 100644
--- a/drivers/gpu/drm/exynos/Kconfig
+++ b/drivers/gpu/drm/exynos/Kconfig
@@ -31,6 +31,14 @@
 	help
 	  Choose this option if you want to use Exynos FIMD for DRM.
 
+config DRM_EXYNOS_DPI
+	bool "EXYNOS DRM parallel output support"
+	depends on DRM_EXYNOS
+	select DRM_PANEL
+	default n
+	help
+	  This enables support for Exynos parallel output.
+
 config DRM_EXYNOS_DP
 	bool "EXYNOS DRM DP driver support"
 	depends on DRM_EXYNOS && ARCH_EXYNOS