xen/evtchn: use xen_vcpu_id mapping

Use the newly introduced xen_vcpu_id mapping to get Xen's idea of vCPU
id for CPU0.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
1 file changed