mfd: lpc_ich: Add a platform device for pinctrl Denverton

This is to cater the need in non-ACPI system whereby a platform device
has to be created in order to bind with the Denverton pinctrl driver.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230926190834.932233-4-andriy.shevchenko@linux.intel.com


Signed-off-by: Lee Jones <lee@kernel.org>