rework in CPUID code (fixed code duplication). Re-enable perfmon reporting in CPUID because Win8/Win10 installation doesn't want to start without perfmon reported. TODO: implement basic perfmon support (at least only fixed counters) because win7-64 doesn't install with perfmon reported but not implemented

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12505 6c8e4198-a580-4521-a02f-c9ae86df1db9