gpio: Add Intel Granite Rapids-D vGPIO driver

This driver provides a basic GPIO driver for the Intel Granite Rapids-D
virtual GPIOs. On SoCs with limited physical pins on the package, the
physical pins controlled by this driver would be exposed on an external
device such as a BMC or CPLD. The virtual GPIO registers are an
interface to firmware, which communicates with the external device that
implements the GPIO hardware functionality.

Signed-off-by: Aapo Vienamo <aapo.vienamo@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>