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/stdio.c b/common/stdio.c
index 49784e3..cbedfdd 100644
--- a/common/stdio.c
+++ b/common/stdio.c
@@ -200,7 +200,7 @@
 		if (strcmp(sdev->name, name) == 0)
 			return sdev;
 	}
-	if (IS_ENABLED(CONFIG_DM_VIDEO)) {
+	if (IS_ENABLED(CONFIG_VIDEO)) {
 		/*
 		 * We did not find a suitable stdio device. If there is a video
 		 * driver with a name starting with 'vidconsole', we can try
@@ -340,7 +340,7 @@
 #if CONFIG_IS_ENABLED(SYS_I2C_LEGACY)
 	i2c_init_all();
 #endif
-	if (IS_ENABLED(CONFIG_DM_VIDEO)) {
+	if (IS_ENABLED(CONFIG_VIDEO)) {
 		/*
 		 * If the console setting is not in environment variables then
 		 * console_init_r() will not be calling iomux_doenv() (which