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/drivers/video/stm32/Kconfig b/drivers/video/stm32/Kconfig
index 95d51bb..4806606 100644
--- a/drivers/video/stm32/Kconfig
+++ b/drivers/video/stm32/Kconfig
@@ -7,7 +7,7 @@
 
 menuconfig VIDEO_STM32
 	bool "Enable STM32 video support"
-	depends on DM_VIDEO
+	depends on VIDEO
 	help
 	  STM32 supports many video output options including RGB and
 	  DSI. This option enables these supports which can be used on