KVM: Portability: Expand the KVM_VCPU_COMM in kvm_vcpu structure.

This patches removes KVM_COMM macro, original it is hold
kvm_vcpu common fields.

Signed-off-by: Zhang Xiantao <xiantao.zhang@intel.com>
Acked-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>