irqchip/loongson-liointc: irqchip add 2.0 version

Add IO interrupt controller support for Loongson-2K1000, different
from the Loongson-3A series is that Loongson-2K1000 has 64 interrupt
sources, 0-31 correspond to the device tree liointc0 device node, and
the other correspond to liointc1 node.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Tested-by: Ming Wang <wangming01@loongson.cn>
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>