perf bench numa: Show more stats of particular threads in verbose mode

In verbose mode perf bench numa shows also GB/s speed, system and user cpu
time for each particular thread. Using of getrusage() can provide much more
per process or per thread stats in future.

Signed-off-by: Petr Holasek <pholasek@redhat.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1429198699-25039-3-git-send-email-pholasek@redhat.com
[ Rename 'usage' variable to not shadow util.h's usage() ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>