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/cmd/Kconfig b/cmd/Kconfig
index 9aac534..3f6bc70 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -1877,7 +1877,7 @@
 
 config CMD_BMP
 	bool "Enable 'bmp' command"
-	depends on DM_VIDEO
+	depends on VIDEO
 	help
 	  This provides a way to obtain information about a BMP-format image
 	  and to display it. BMP (which presumably stands for BitMaP) is a
@@ -2163,7 +2163,7 @@
 
 config CMD_VIDCONSOLE
 	bool "lcdputs and setcurs"
-	depends on DM_VIDEO
+	depends on VIDEO
 	default y
 	help
 	  Enabling this will provide 'setcurs' and 'lcdputs' commands which