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/configs/evb-px30_defconfig b/configs/evb-px30_defconfig
index 3ed5c3e..5c62163 100644
--- a/configs/evb-px30_defconfig
+++ b/configs/evb-px30_defconfig
@@ -109,7 +109,7 @@
 CONFIG_USB_EHCI_GENERIC=y
 CONFIG_USB_GADGET=y
 CONFIG_USB_GADGET_DWC2_OTG=y
-CONFIG_DM_VIDEO=y
+CONFIG_VIDEO=y
 CONFIG_DISPLAY=y
 CONFIG_SPL_TINY_MEMSET=y
 CONFIG_TPL_TINY_MEMSET=y