pinctrl: elkhartlake: Add support for DSW community

Hardware has a DSW (Deep Sleep Well) community that might be exposed
by some BIOSes. Add support for it in the driver.

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