MIPS: Support CPU topology files in sysfs

MIPS: Support CPU topology files in sysfs

This patch is prepared for Loongson's NUMA support, it offer meaningful
sysfs files such as physical_package_id, core_id, core_siblings and
thread_siblings in /sys/devices/system/cpu/cpu?/topology.

Signed-off-by: Huacai Chen <[email protected]>
Reviewed-by: Andreas Herrmann <[email protected]>
Cc: John Crispin <[email protected]>
Cc: Steven J. Hill <[email protected]>
Cc: Aurelien Jarno <[email protected]>
Cc: [email protected]
Cc: Fuxin Zhang <[email protected]>
Cc: Zhangjin Wu <[email protected]>
Patchwork: https://patchwork.linux-mips.org/patch/7184/
Signed-off-by: Ralf Baechle <[email protected]>