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/rockchip/Kconfig b/drivers/video/rockchip/Kconfig
index 0ade631..b038663 100644
--- a/drivers/video/rockchip/Kconfig
+++ b/drivers/video/rockchip/Kconfig
@@ -10,7 +10,7 @@
 
 menuconfig VIDEO_ROCKCHIP
 	bool "Enable Rockchip Video Support"
-	depends on DM_VIDEO
+	depends on VIDEO
 	help
 	  Rockchip SoCs provide video output capabilities for High-Definition
 	  Multimedia Interface (HDMI), Low-voltage Differential Signalling