pinctrl: baytrail: Use dedicated helpers for chained IRQ handlers

Instead of relying on the fact that the parent IRQ chip supports
fasteoi mode and calling the respective callback at the end of
the interrupt handler, surround it with enter and exit helpers
for chained IRQ handlers which will consider all possible cases.

This in particular unifies how GPIO drivers handle IRQ.

Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>