drivers/perf: hisi: Add identifier sysfs file

mainline inclusion
from mainline-v5.10-rc3
commit ac4511c9
category: feature
bugzilla: 175148
CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ac4511c9364c9a6390e8585cdd4596103bca16eb



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To allow userspace to identify the specific implementation of the device,
add an "identifier" sysfs file.

Encoding is as follows (same for all uncore drivers):
hi1620: 0x0
hi1630: 0x30

Signed-off-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/1602149181-237415-2-git-send-email-john.garry@huawei.com


Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>