tools/power/x86/intel-speed-select: Increase CPU count

Increase CPU count so that more than 64 is supported in one request.

For example:
sudo ./intel-speed-select -d --cpu 0-66 core-power assoc -clos 0
The above command stops at 63. With this change, it can support more
CPU numbers from 0-255.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>