- use utility macros for CPU family/model checking
- limit Intel P6 quirk to pre-Nehalem models (taken from OpenSolaris)
- add AMD GartTblWkEn quirk for families 0Fh and 10h; I haven't experienced
any problems without the quirk but both Linux and OpenSolaris do this
- slightly re-arrange quirk code to provide for the future generalization
and separation of vendor-specific quirk functions
Reviewed by: jhb
MFC after: 1 week