The physical address of the memory used for the guest VMCB is already
present in Vcpu_data. Use the information there instead of storing the
physical address in the host data area, thereby freeing up 8 bytes for
a bigger Mmio class.
Issue #4081
Make naming across architectures coherent by renaming Vm_state to
Vcpu_state, to reflect that it contains the state of a Vcpu and not that
of an entire VM.
Ref #4968
