drivers/perf: hisi: Add description for HNS3 PMU driver

mainline inclusion
from mainline-arm64-upstream
commit 39915b6b
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5KAX7
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=39915b6b5fc2



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HNS3 PMU End Point device is supported on HiSilicon HIP09 platform, so
add document hns3-pmu.rst to provide guidance on how to use it.

Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Reviewed-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Link: https://lore.kernel.org/r/20220628063419.38514-2-huangguangbin2@huawei.com


Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Jiantao Xiao <xiaojiantao1@h-partners.com>
Reviewed-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-by: Yang Jihong <yangjihong1@huawei.com>
Reviewed-by: Jian Shen <shenjian15@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>