arm64: Add HWCAP for self-synchronising virtual counter

mainline inclusion
from mainline-v5.16-rc1
commit fee29f00
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4QCBG


CVE: NA

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

Since userspace can make use of the CNTVSS_EL0 instruction, expose
it via a HWCAP.

Suggested-by: Will Deacon <will@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211017124225.3018098-18-maz@kernel.org


Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>