Add the numa_topology object to return the list of numa nodes together
with their cpus. It will replace the numa code in header.c and will be
used from 'perf record' in the following patches.

Add the following interface functions to load numa details:

  struct numa_topology *numa_topology__new(void);
  void numa_topology__delete(struct numa_topology *tp);

And replace the current (copied) local interface, with no functional
changes.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190219095815.15931-4-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>