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/theadorable_defconfig b/configs/theadorable_defconfig
index fd569e5..e64a605 100644
--- a/configs/theadorable_defconfig
+++ b/configs/theadorable_defconfig
@@ -8,6 +8,7 @@
 CONFIG_SPL_SERIAL_SUPPORT=y
 CONFIG_SPL_SPI_FLASH_SUPPORT=y
 CONFIG_SPL_SPI_SUPPORT=y
+CONFIG_VIDEO=y
 CONFIG_DEFAULT_DEVICE_TREE="armada-xp-theadorable"
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
 CONFIG_FIT=y