Revert "x86, hotplug: Use mwait to offline a processor, fix the legacy case"

Revert "x86, hotplug: Use mwait to offline a processor, fix the legacy case"

This reverts commit 226917b0735f31cf5c704e07fdd590d99bbfae58 (upstream
ea53069231f9317062910d6e772cca4ce93de8c8 and
a68e5c94f7d3dd64fef34dd5d97e365cae4bb42a and
ce5f68246bf2385d6174856708d0b746dc378f20 all mushed together) as
Jonathan Nieder reports that this causes a regression on some hardware.

More details can be found at http://bugs.debian.org/622259

Cc: Jonathan Nieder <jrnieder@gmail.com>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Len Brown <len.brown@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>