kvm: arm64: make ID registers configurable

hulk inclusion
category: feature
bugzilla: NA
CVE: NA

It's time to make ID registers configurable.  When userspace (but not
guest) want to set the values of ID registers, save the value in
kvm_arch_vcpu so that guest can read the modified values.

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Peng Liang <liangpeng10@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>