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/mx6cuboxi_defconfig b/configs/mx6cuboxi_defconfig
index 27c3d3b..7bcb031 100644
--- a/configs/mx6cuboxi_defconfig
+++ b/configs/mx6cuboxi_defconfig
@@ -10,6 +10,7 @@
 CONFIG_SPL_MMC_SUPPORT=y
 CONFIG_SPL_SERIAL_SUPPORT=y
 CONFIG_SPL_WATCHDOG_SUPPORT=y
+CONFIG_VIDEO=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=arch/arm/imx-common/spl_sd.cfg,MX6QDL"
 CONFIG_SPL=y
 CONFIG_HUSH_PARSER=y