Add a new option '--cputype' to 'perf list' to display core-only PMU
events or atom-only PMU events.

Each hybrid PMU event has been assigned with a PMU name, this patch
compares the PMU name before listing the result.

For example:

  perf list --cputype atom
  ...
  cache:
    core_reject_l2q.any
         [Counts the number of request that were not accepted into the L2Q because the L2Q is FULL. Unit: cpu_atom]
  ...

The "Unit: cpu_atom" is displayed in the brief description section
to indicate this is an atom event.
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210903025239.22754-1-yao.jin@linux.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>