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/exynos/Kconfig b/drivers/video/exynos/Kconfig
index 37e661b..599d19d 100644
--- a/drivers/video/exynos/Kconfig
+++ b/drivers/video/exynos/Kconfig
@@ -1,7 +1,7 @@
 
 menuconfig VIDEO_EXYNOS
 	bool "Enable Exynos video support"
-	depends on DM_VIDEO
+	depends on VIDEO
 	help
 	  Enable support for various video output options on Exynos SoCs.