s390/topology: fix core id vs physical package id mix-up

The current topology code confuses core id vs physical package id.

In other words /sys/devices/system/cpu/cpuX/topology/core_id
displays the physical_package_id (aka socket id) instead of the
core id.
The physical_package_id sysfs attribute always displays "-1"
instead of the socket id.

Fix this mix-up with a small patch which defines and initializes
topology_physical_package_id correctly and fixes the broken
core id handling.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>