opos6uldev: migrate to DM_VIDEO

Migrate to DM_VIDEO, update the device tree and remove code that is no
longer necessary.

Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
diff --git a/configs/opos6uldev_defconfig b/configs/opos6uldev_defconfig
index 44236e9..352d10a 100644
--- a/configs/opos6uldev_defconfig
+++ b/configs/opos6uldev_defconfig
@@ -95,6 +95,7 @@
 CONFIG_USB_GADGET_PRODUCT_NUM=0xa4a5
 CONFIG_CI_UDC=y
 CONFIG_USB_GADGET_DOWNLOAD=y
-CONFIG_VIDEO=y
+CONFIG_DM_VIDEO=y
+CONFIG_SYS_WHITE_ON_BLACK=y
 CONFIG_OF_LIBFDT_OVERLAY=y
 # CONFIG_EFI_LOADER is not set