MIPS: Netlogic: Move cores per node out of multi-node.h

Use the current_cpu_data package field to get the node of the current CPU.

This allows us to remove xlp_cores_per_node and move nlm_threads_per_node()
and nlm_cores_per_node() to netlogic/common.h, which simplifies code.

Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8889/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>