irqchip/gic-v3-its: its support herbination

hulk inclusion
category: bugfix
bugzilla: 26326
CVE: NA

-------------------------------------------------

Currently, when we test hibernation, it will fail at the ITS.
[11384.327419] Call trace:
[11384.329854]  dump_backtrace+0x0/0x180
[11384.333503]  show_stack+0x14/0x20
[11384.336805]  dump_stack+0x8c/0xac
[11384.340107]  dequeue_task_idle+0x2c/0x68
[11384.344016]  do_set_cpus_allowed+0x5c/0x148
[11384.348186]  cpuset_cpus_allowed_fallback+0x1c/0x48
[11384.353050]  select_fallback_rq+0x17c/0x220
[11384.355310] ITS queue not draining
[11384.357219]  sched_cpu_dying+0x328/0x368
[11384.364513]  cpuhp_invoke_callback+0xc0/0x1f0
[11384.368856]  _cpu_up+0x164/0x1e0
[11384.372070]  enable_nonboot_cpus+0x7c/0xf8
[11384.376153]  hibernation_snapshot+0x1c0/0x348
[11384.380496]  hibernate+0xf4/0x290
[11384.383797]  state_store+0x70/0xa0
[11384.387185]  kobj_attr_store+0x14/0x28
[11384.390921]  sysfs_kf_write+0x4c/0x60
[11384.394569]  kernfs_fop_write+0x11c/0x1d0
[11384.398566]  __vfs_write+0x1c/0x138
[11384.402041]  vfs_write+0xb4/0x190
[11384.405342]  ksys_write+0x50/0xa0
[11384.408643]  __arm64_sys_write+0x14/0x20
[11384.412552]  el0_svc_common+0x100/0x168
[11384.416374]  el0_svc_handler+0x4c/0x68
[11384.420109]  el0_svc+0x8/0xc
[11384.422984] Unable to handle kernel NULL pointer dereference at
virtual address 0000000000000000

The its doesn't support hibernate, when hibernate() calls, the its
doesn't suspend() and resume() successfully.

Add its herbinate state to support its suspend and resume correctly.

https://lkml.org/lkml/2019/12/2/270



Signed-off-by: Hongbo Yao <yaohongbo@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>