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/common/fdt_simplefb.c b/common/fdt_simplefb.c
index 9519564..71d4c8f 100644
--- a/common/fdt_simplefb.c
+++ b/common/fdt_simplefb.c
@@ -82,7 +82,7 @@
 	return fdt_simplefb_configure_node(blob, off);
 }
 
-#if CONFIG_IS_ENABLED(DM_VIDEO)
+#if CONFIG_IS_ENABLED(VIDEO)
 int fdt_simplefb_enable_and_mem_rsv(void *blob)
 {
 	struct fdt_memory mem;