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/pico-imx6_defconfig b/configs/pico-imx6_defconfig
index ef72461..63fdca3 100644
--- a/configs/pico-imx6_defconfig
+++ b/configs/pico-imx6_defconfig
@@ -88,7 +88,7 @@
 CONFIG_USB_GADGET_VENDOR_NUM=0x0525
 CONFIG_USB_GADGET_PRODUCT_NUM=0xa4a5
 CONFIG_CI_UDC=y
-CONFIG_DM_VIDEO=y
+CONFIG_VIDEO=y
 CONFIG_VIDEO_LOGO=y
 # CONFIG_BACKLIGHT is not set
 # CONFIG_CMD_VIDCONSOLE is not set