s390/numa: pin all possible cpus to nodes early

It is required to have an early static cpu to node mapping. This patch
pins all possible cpus to nodes for which no topology information is
present. Since there is no interface available which would allow to
tell where a non-present cpu would appear topology-wise, simply use a
round robin algorithm.
Right now this makes sure that the cpu_to_node() function will return
the same value for a cpu during the life time of the system.

Acked-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>