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/arch/arm/mach-imx/mx6/Kconfig b/arch/arm/mach-imx/mx6/Kconfig
index c7a03e5..752c57f 100644
--- a/arch/arm/mach-imx/mx6/Kconfig
+++ b/arch/arm/mach-imx/mx6/Kconfig
@@ -249,7 +249,7 @@
 	select DM_MMC
 	select PCI
 	select DM_SCSI
-	select DM_VIDEO
+	select VIDEO
 	select OF_CONTROL
 	select SUPPORT_SPL
 	imply CMD_DM