pinctrl: cherryview: add option to set open-drain pin config

On some CHV platforms, we need an option to configure the
open-drain setting for these pins.  This adds support for the
PIN_CONFIG_DRIVE_PUSH_PULL and PIN_CONFIG_DRIVE_OPEN_DRAIN to
disable/enable open-drain mode for a specific pin.

Signed-off-by: Dan O'Donovan <dan@emutex.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>