MINOR: cpu-topo: split cpu_dump_topology() to show its summary in show dev

MINOR: cpu-topo: split cpu_dump_topology() to show its summary in show dev

cpu_dump_topology() prints details about each enabled CPU and a summary with
clusters info and thread-cpu bindings. The latter is often usefull for
debugging and we want to add it in the 'show dev' output.

So, let's split cpu_dump_topology() in two parts: cpu_topo_debug() to print the
details about each enabled CPU; and cpu_topo_dump_summary() to print only the
summary.

In the next commit we will modify cpu_topo_dump_summary() to write into local
trash buffer and it could be easily called from debug_parse_cli_show_dev().