video: add nexell video driver (display/video driver)

Changes in relation to FriendlyARM's U-Boot nanopi2-v2016.01:
- nexell_display.c: Changed to DM, CONFIG_FB_ADDR can not be used
  anymore because framebuffer is allocated by video_reserve() in
  video-uclass.c. Therefore code changed appropriately.
- '#ifdef CONFIG...' changed to 'if (IS_ENABLED(CONFIG...))' where
  possible (and similar).
- livetree API (dev_read_...) is used instead of fdt one (fdt...).

Signed-off-by: Stefan Bosch <stefan_b@posteo.net>
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 89ad603..55f4fa4 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -644,6 +644,16 @@
 
 source "drivers/video/imx/Kconfig"
 
+config VIDEO_NX
+	bool "Enable video support on Nexell SoC"
+	depends on ARCH_S5P6818 || ARCH_S5P4418
+	help
+	   Nexell SoC supports many video output options including eDP and
+	   HDMI. This option enables this support which can be used on devices
+	   which have an eDP display connected.
+
+source "drivers/video/nexell/Kconfig"
+
 config VIDEO
 	bool "Enable legacy video support"
 	depends on !DM_VIDEO