Convert CONFIG_VIDEO to Kconfig

This converts the following to Kconfig:
   CONFIG_VIDEO

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Jagan Teki <jteki@openedev.com>
diff --git a/configs/mcx_defconfig b/configs/mcx_defconfig
index 28837f9..767f433 100644
--- a/configs/mcx_defconfig
+++ b/configs/mcx_defconfig
@@ -3,6 +3,7 @@
 # CONFIG_SPL_GPIO_SUPPORT is not set
 # CONFIG_SPL_EXT_SUPPORT is not set
 CONFIG_TARGET_MCX=y
+CONFIG_VIDEO=y
 CONFIG_FIT=y
 CONFIG_BOOTDELAY=3
 CONFIG_SPL=y