!387 kvm: arm64: fix some pvsched bugs

Merge Pull Request from: @yezengruan 
 
kvm: arm64: fix some pvsched bugs

1. Clear kvm_vcpu_arch::pvsched::base on vcpu reset
The guest memory will otherwise be corrupted by KVM if we reboot into
an old guest kernel which is **not** aware of the pvsched feature.

2. Fix boot cpu pvsched init abnormal
The pv_sched_init was called too early in the boot in setup_arch, hence
pvsched_vcpu_state was not initializedfo vcpu 0.

https://gitee.com/openeuler/kernel/issues/I6E2VI?from=project-issue 
 
Link:https://gitee.com/openeuler/kernel/pulls/387

 

Reviewed-by: Kevin Zhu <zhukeqian1@huawei.com>
Reviewed-by: Zheng Zengkai <zhengzengkai@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>