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/mx53ppd_defconfig b/configs/mx53ppd_defconfig
index 7fadb6c..b54c90e 100644
--- a/configs/mx53ppd_defconfig
+++ b/configs/mx53ppd_defconfig
@@ -77,7 +77,7 @@
 CONFIG_USB_ETHER_ASIX=y
 CONFIG_USB_ETHER_MCS7830=y
 CONFIG_USB_ETHER_SMSC95XX=y
-CONFIG_DM_VIDEO=y
+CONFIG_VIDEO=y
 CONFIG_SYS_WHITE_ON_BLACK=y
 CONFIG_VIDEO_IPUV3=y
 CONFIG_WATCHDOG_TIMEOUT_MSECS=8000