tools/power/x86/intel-speed-select: Account for missing sysfs for die_id

tools/power/x86/intel-speed-select: Account for missing sysfs for die_id

Some older kernels will not have support to get CPU die_id from the
sysfs. This requires several back ports. But the tool depends on getting
die_id to match to correct CPU.

Relax this restriction and use die_id as 0 when die_id is missing. This
is not a problem as we don't have any multi-die processors with Intel SST
support.

This helps in running this tool on older kernels with just Intel SST
drivers back ported.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://lore.kernel.org/platform-driver-x86/57d6648282491906e0e1f70fe3b9a44f72cec90d.camel@intel.com/
Signed-off-by: Hans de Goede <hdegoede@redhat.com>