tools/power turbostat: correctly display more than 2 threads/core

Without this update, turbostat displays only 2 threads per core.
Some processors, such as Xeon Phi, have more.

Signed-off-by: Dasaratharaman Chandramouli <dasaratharaman.chandramouli@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>