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/board/atmel/sama5d3xek/sama5d3xek.c b/board/atmel/sama5d3xek/sama5d3xek.c
index 132e7fa..008f1db 100644
--- a/board/atmel/sama5d3xek/sama5d3xek.c
+++ b/board/atmel/sama5d3xek/sama5d3xek.c
@@ -186,7 +186,7 @@
 	strcat(name, "ek.dtb");
 	env_set("dtb_name", name);
 #endif
-#ifdef CONFIG_DM_VIDEO
+#ifdef CONFIG_VIDEO
 	at91_video_show_board_info();
 #endif
 	return 0;