KVM: nVMX: remove unnecessary double caching of MAXPHYADDR

After speed-up of cpuid_maxphyaddr() it can be called frequently:
instead of heavyweight enumeration of CPUID entries it returns a cached
pre-computed value. It is also inlined now. So caching its result became
unnecessary and can be removed.

Signed-off-by: Eugene Korenevsky <ekorenevsky@gmail.com>
Message-Id: <20150329205644.GA1258@gnote>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>