tools/power/x86/intel-speed-select: Special handling for CPU 0 online/offline

When "-o" option for force online/offline is used with command:
perf-profile set-config-level

If the config level calls for CPU 0 online/offline, then call fails
as there is special kernel setup required for CPU 0 online/offline
and the currently not setup for that.

But when call is for online CPU 0, then don't fail. Just warn that
this system is not setup for CPU 0 online/offline.

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