2.6.25 regression: powertop says 120K wakeups/sec

Patch to fix huge number of wakeups reported due to recent changes in
processor_idle.c. The problem was that the entry_method determination was
broken due to one of the recent commits (bc71bec91f987) causing
C1 entry to not to go to halt.

http://lkml.org/lkml/2008/3/22/124

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>