perf mem: Add 'op' output field

This is an actual example of the he_mem_stat based sample breakdown.  It
uses 'mem_op' field of union perf_mem_data_src which means memory
operations.

It'd have basically 'load' or 'store' which can be useful if PMU doesn't
have separate events for them like IBS or SPE.  In addition, there's an
entry in case load and store happen at the same time.  Also adds entries
for prefetching and execution.

  $ perf mem report -F +op -s comm --stdio
  # To display the perf.data header info, please use --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 4K of event 'ibs_op//'
  # Total weight : 9559
  # Sort order   : comm
  #
  #                   --------------------- Mem Op ----------------------
  # Overhead  Samples   Load  Store Ld+St Pfetch  Exec  Other   N/A   N/A  Command
  # ........  ....... ...................................................  ...............
  #
      44.85%     4077  21.1%  30.7%  0.0%   0.0%  0.0%  48.3%  0.0%  0.0%  swapper
      26.82%       45  98.8%   0.3%  0.0%   0.0%  0.0%   0.9%  0.0%  0.0%  netsli-prober
       7.19%      442  51.7%  13.7%  0.0%   0.0%  0.0%  34.6%  0.0%  0.0%  perf
       5.81%       75  89.7%   2.2%  0.0%   0.0%  0.0%   8.1%  0.0%  0.0%  qemu-system-ppc
       4.77%        1 100.0%   0.0%  0.0%   0.0%  0.0%   0.0%  0.0%  0.0%  notifications_c
       1.77%       10  95.9%   1.2%  0.0%   0.0%  0.0%   3.0%  0.0%  0.0%  MemoryReleaser
       0.77%       32  71.6%   4.1%  0.0%   0.0%  0.0%  24.3%  0.0%  0.0%  DefaultEventMan
       0.19%       10  66.7%  22.2%  0.0%   0.0%  0.0%  11.1%  0.0%  0.0%  gnome-shell

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Link: https://lore.kernel.org/r/20250430205548.789750-8-namhyung@kernel.org


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