This converts the following to Kconfig:
   CONFIG_CMD_HDMIDETECT

Note that we cannot do 'default y if VIDEO' because this option is only
enabled for a small subset of mx6 boards. Also this command is is not a
great implementation (it doesn't use driver model).
Signed-off-by: NSimon Glass <sjg@chromium.org>
Reviewed-by: NTom Rini <trini@konsulko.com>