x86, cpu: Package Level Thermal Control, Power Limit Notification definitions

Add package level thermal and power limit feature support.

The two MSRs and features are new starting with Intel's Sandy Bridge processor.

Please check Intel 64 and IA-32 Architectures SDMV Vol 3A 14.5.6 Power Limit
Notification and 14.6 Package Level Thermal Management.

This patch also fixes a bug which defines reverse THERM_INT_LOW_ENABLE bit and
THERM_INT_HIGH_ENABLE bit.

[ hpa: fixed up against current tip:x86/cpu ]

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
LKML-Reference: <1280448826-12004-2-git-send-email-fenghua.yu@intel.com>
Reviewed-by: Len Brown <len.brown@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>