sh: Convert Cayman boards from hw_interrupt_type to irq_chip

I've been unable to even compile-test this change because I don't have
an sh5 toolchain. All uses of hw_interrupt_type for SuperH boards have
now been converted to use irq_chip.

Signed-off-by: Matt Fleming <mjf@gentoo.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>