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/rock-pi-n8-rk3288_defconfig b/configs/rock-pi-n8-rk3288_defconfig
index 6227ad3..bd2fb5d 100644
--- a/configs/rock-pi-n8-rk3288_defconfig
+++ b/configs/rock-pi-n8-rk3288_defconfig
@@ -83,7 +83,7 @@
 # CONFIG_USB_KEYBOARD_FN_KEYS is not set
 CONFIG_USB_GADGET=y
 CONFIG_USB_GADGET_DWC2_OTG=y
-CONFIG_DM_VIDEO=y
+CONFIG_VIDEO=y
 CONFIG_DISPLAY=y
 CONFIG_VIDEO_ROCKCHIP=y
 CONFIG_DISPLAY_ROCKCHIP_HDMI=y