tools/power/x86/intel-speed-select: Fix last cpu number

Here topology_max_cpus is used for total CPU count, not the last CPU
number. So remove "-1".

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