KVM: PPC: e500mc: Move reset of oldpir below call to kvm_vcpu_init()

Move the initialization of oldpir so that the call to kvm_vcpu_init() is
at the top of kvmppc_core_vcpu_create_e500mc().  oldpir is only use
when loading/putting a vCPU, which currently cannot be done until after
kvm_arch_vcpu_create() completes.  Reording the call to kvm_vcpu_init()
paves the way for moving the invocation to common PPC code.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>