pinctrl: intel: Embed struct pingroup into struct intel_pingroup

Add a new member to the struct intel_pingroup to cover generic
pin control group parameters. The idea is to convert all users
(one-by-one) to it and drop old members later on.

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