KVM/arm64 fixes for 6.18, take #3
- Only adjust the ID registers when no irqchip has been created once
per VM run, instead of doing it once per vcpu, as this otherwise
triggers a pretty bad conbsistency check failure in the sysreg code.
- Make sure the per-vcpu Fine Grain Traps are computed before we load
the system registers on the HW, as we otherwise start running without
anything set until the first preemption of the vcpu.