MIPS: JZ4740: support >32 interrupts

MIPS: JZ4740: support >32 interrupts

On newer Ingenic SoCs the interrupt controller supports more than 32
interrupts, which it does by duplicating the registers at intervals
of 0x20 bytes within its address space. Add support for an arbitrary
number of interrupts using multiple generic chips, and provide the
number of chips to register from the interrupt controller probe
function.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: Brian Norris <computersforpeace@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/10141/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>