perf tools: Add support for sorting on the iaddr

Sorting on 'symbol' gives to broad a resolution as it can cover a range
of IP address.  Use the iaddr instead to get proper sorting on IP
addresses.  Need to use the 'mem_sort' feature of perf record.

New sort option is: symbol_iaddr, header label is 'Code Symbol'.

  $ perf mem report --stdio -F +symbol_iaddr
  # Overhead       Samples  Code Symbol              Local Weight
  # ........  ............  ........................ ............
  #
      54.08%             1  [k] nmi_handle           192
       4.51%             1  [k] finish_task_switch   16
       3.66%             1  [.] malloc               13
       3.10%             1  [.] __strcoll_l          11

Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1444068369-20978-8-git-send-email-jolsa@kernel.org


Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>