board: at91sam9x5ek: 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 ebd865a..7e85b69 100644
--- a/arch/arm/mach-at91/Kconfig
+++ b/arch/arm/mach-at91/Kconfig
@@ -141,6 +141,7 @@
 	select AT91SAM9X5
 	select SUPPORT_SPL
 	select BOARD_EARLY_INIT_F
+	select BOARD_LATE_INIT
 
 config TARGET_SAMA5D2_PTC
 	bool "SAMA5D2 PTC board"