pinctrl: intel: fix bug of register offset calculation

The group size for registers PADCFGLOCK, HOSTSW_OWN, GPI_IS,
GPI_IE, are not 24 for Broxton, Add a parameter to allow
different platform to set correct value.

Signed-off-by: Qi Zheng <qi.zheng@intel.com>
Signed-off-by: Qipeng Zha <qipeng.zha@intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>