spapr: Move SMT-related properties out of skeleton fdt

spapr: Move SMT-related properties out of skeleton fdt

The upcoming support of the "ibm,client-architecture-support"
reconfiguration call will be able to change dynamically the number
of threads per core (SMT mode). From the device tree prospective
this does not change the number of CPU nodes (as it is one node per
a CPU core) but affects content and size of the ibm,ppc-interrupt-server#s
and ibm,ppc-interrupt-gserver#s properties.

This moves ibm,ppc-interrupt-server#s and ibm,ppc-interrupt-gserver#s
out of the device tree skeleton.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>