pinctrl: baytrail: Save pin context over system sleep

The BIOS might reconfigure pins as it needs when S3 is entered. This might
cause drivers using the GPIOs to fail because the state was wrong or
interrupts stopped working.

Fix this by saving and restoring enough pin context over system sleep.

Reported-by: Hans Holmberg <hans.holmberg@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>