pinctrl: intel: Convert to generic_handle_domain_irq()

Replace construct that matches generic_handle_irq(irq_find_mapping())
to a single call to generic_handle_domain_irq().

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