arm64: Add HWCAP advertising FEAT_WFXT

mainline inclusion
from mainline-v5.19-rc1
commit 69bb02eb
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I6YAMV
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=69bb02ebc38ace438c9cd7c5315cfe43862b51fe



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In order to allow userspace to enjoy WFET, add a new HWCAP that
advertises it when available.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419182755.601427-9-maz@kernel.org


Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>