[PATCH] intel_pmic_gpio: modify EOI handling following change of kernel irq subsystem

Latest kernel has many changes in IRQ subsystem and its interfaces, like adding
"irq_eoi" for struct irq_chip, this patch will make it support both the new
and old interface.

Cc: Alek Du <alek.du@intel.com>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>