video: Rename CONFIG_DM_VIDEO to CONFIG_VIDEO

Now that all the old code is gone, rename this option. Driver model
migration is now complete.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/chromebit_mickey_defconfig b/configs/chromebit_mickey_defconfig
index 657db66..df94cac 100644
--- a/configs/chromebit_mickey_defconfig
+++ b/configs/chromebit_mickey_defconfig
@@ -99,7 +99,7 @@
 # CONFIG_SPL_DM_USB is not set
 CONFIG_USB_DWC2=y
 CONFIG_ROCKCHIP_USB2_PHY=y
-CONFIG_DM_VIDEO=y
+CONFIG_VIDEO=y
 # CONFIG_VIDEO_BPP8 is not set
 CONFIG_DISPLAY=y
 CONFIG_VIDEO_ROCKCHIP=y