kvm: arm64: add KVM_CAP_ARM_CPU_FEATURE extension

hulk inclusion
category: feature
bugzilla: 48052
CVE: NA

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Add KVM_CAP_ARM_CPU_FEATURE extension for userpace to check whether KVM
supports to set CPU features in AArch64.

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Peng Liang <liangpeng10@huawei.com>
Reviewed-by: Zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>