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/Kconfig b/drivers/video/Kconfig
index 8f0b005..c841b99 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -4,7 +4,7 @@
 
 menu "Graphics support"
 
-config DM_VIDEO
+config VIDEO
 	bool "Enable driver model support for LCD/video"
 	depends on DM
 	help
@@ -14,7 +14,7 @@
 	  option compiles in the video uclass and routes all LCD/video access
 	  through this.
 
-if DM_VIDEO
+if VIDEO
 
 config VIDEO_LOGO
 	bool "Show the U-Boot logo on the display"
@@ -891,6 +891,6 @@
 	help
 	  Support display of bitmaps file with 32-bit-per-pixel.
 
-endif # DM_VIDEO
+endif # VIDEO
 
 endmenu