x86/Intel: work around Xeon 7400 series erratum AAI65

x86/Intel: work around Xeon 7400 series erratum AAI65

Linux commit 40e2d7f9b5dae048789c64672bf3027fbb663ffa ("x86 idle:
Repair large-server 50-watt idle-power regression") tells us that this
applies not just to the named Xeon 7400 series, but also NHM-EX and
WSM-EX; sadly Intel's documentation is so badly searchable that I
wasn't able to locate the respective errata (and hence can't quote
their numbers here).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
master commit: 96d1b237ae9b2f2718bb1c59820701f17d3d86e0
master date: 2014-03-17 16:47:22 +0100