tools/power turbostat: Fix incorrect sorting of PMT telemetry

tools/power turbostat: Fix incorrect sorting of PMT telemetry

The pmt_telemdir_sort() comparison function was returning a boolean
value (0 or 1) instead of the required negative, zero, or positive
value for proper sorting. This caused unpredictable and incorrect
ordering of telemetry directories named telem0, telem1, ..., telemN.
Update the comparison logic to return -1, 0, or 1 based on the
numerical value extracted from the directory name, ensuring correct
numerical ordering when using scandir.

This change improves stability and correctness when iterating PMT
telemetry directories.

Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>