tools/power turbostat: Cleanup package_id

tools/power turbostat: Cleanup package_id

The kernel topology sysfs uses the name "physical_package_id"
because it is allowed to be sparse.

Inside Turbostat, that physical package_id namespace is the only
package_id namespace, so re-name it to simply be "package_id"
in cpus[].

Delete the redundant copy of package_id in pkg_data.
Rely instead on the single copy of the truth in cpus[].

No functional change.

Signed-off-by: Len Brown <len.brown@intel.com>