pinctrl: tangier: Enable 910 Ohm bias

Family 7 (I2C) supports special bias value, i.e. 910 Ohm.

Enable it for configuring pin.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Raag Jadav <raag.jadav@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>