KVM: aarch64: Rebase up to v6.5 (first round)

JIRA: https://issues.redhat.com/browse/RHEL-1760
Upstream Status: v6.5
Tested: Passed on virt-install, kvm/selftests, kvm-unit-tests, migration, pci-passthrough

This is the first round to rebase kvm-arm to upstream v6.5, which just pick up those independent commit. This merge request contains several parts:

1. Eager page splitting
2. Support writable cpuid reg from userspace
3. misc stuff

And the omitted things in the first round include:

1. FF-A proxy for pKVM
2. Support for Armv8.8 memcpy instructions in userspace
3. Permission Indirection Extension
4. Allow using VHE in the nVHE hypervisor
5. Some Rename Register per auto-gen tools
6. Fix setting SVE and SME traps in hVHE

Signed-off-by: Shaoqin Huang shahuang@redhat.com