pinctrl: denverton: Enable platform device in the absence of ACPI enumeration

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

Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>