board: sama5d4_xplained: Convert to CONFIG_DM_VIDEO

Convert the board to support the video driver model, add the device
tree node, and remove the unnecessary code.

Signed-off-by: Wenyou Yang <wenyou.yang@microchip.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-at91/Kconfig b/arch/arm/mach-at91/Kconfig
index b4967f9..ebd865a 100644
--- a/arch/arm/mach-at91/Kconfig
+++ b/arch/arm/mach-at91/Kconfig
@@ -186,6 +186,7 @@
 	select SAMA5D4
 	select SUPPORT_SPL
 	select BOARD_EARLY_INIT_F
+	select BOARD_LATE_INIT
 
 config TARGET_SAMA5D4EK
 	bool "SAMA5D4 Evaluation Kit"