irqchip: phytium-2500: Add interrupt controller driver

hulk inclusion
category: Feature
bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=52


CVE: NA

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To enable support for Phytium ARMv8 S2500/FT-2500 SoC
and 2-Processor server, add phytium-2500 specific interrupt
controller driver based on ARM original irq-gic-v3.c
and irq-gic-v3-its.c

Signed-off-by: Mao HongBo <maohongbo@phytium.com.cn>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Cheng Jian <cj.chengjian@huawei.com>