misc: microchip: pci1xxxx: Add gpio irq handler and irq helper functions irq_ack...

misc: microchip: pci1xxxx: Add gpio irq handler and irq helper functions irq_ack, irq_mask, irq_unmask and irq_set_type of irq_chip.

The helper functions irq_set_type, irq_mask, irq_unmask and
irq_ack configure the interrupt type, mask, unmask and
acknowledge the interrupts.

Signed-off-by: Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>
Link: https://lore.kernel.org/r/20220824200047.150308-5-kumaravel.thiagarajan@microchip.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>