board: sama5d2_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/configs/sama5d2_xplained_mmc_defconfig b/configs/sama5d2_xplained_mmc_defconfig
index 215961a..87fc049 100644
--- a/configs/sama5d2_xplained_mmc_defconfig
+++ b/configs/sama5d2_xplained_mmc_defconfig
@@ -82,3 +82,5 @@
 CONFIG_USB_STORAGE=y
 CONFIG_USB_GADGET=y
 CONFIG_USB_GADGET_ATMEL_USBA=y
+CONFIG_DM_VIDEO=y
+CONFIG_ATMEL_HLCD=y