mfd: lpc_ich: Enable watchdog on Intel Apollo Lake PCH

Assign iTCO_version which effectively enables watchdog device on
Intel Apollo Lake PCH.

Signed-off-by: Tan Jui Nee <jui.nee.tan@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>