perf c2c report: Add c2c related stats stdio output

Display c2c related configuration options/setup.
So far it's output of monitored events:

  $ perf c2c report --stats
  ...

  =================================================
                   c2c details
  =================================================
    Events                            : cpu/mem-loads,ldlat=50/pp
                                      : cpu/mem-stores/pp

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-ypz84f3a9fumyttrxurm458z@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>