perf parse-events: Handle uncore event aliases in small groups properly

Perf stat doesn't count the uncore event aliases from the same uncore
block in a group, for example:

  perf stat -e '{unc_m_cas_count.all,unc_m_clockticks}' -a -I 1000
  #           time             counts unit events
       1.000447342      <not counted>      unc_m_cas_count.all
       1.000447342      <not counted>      unc_m_clockticks
       2.000740654      <not counted>      unc_m_cas_count.all
       2.000740654      <not counted>      unc_m_clockticks

The output is very misleading. It gives a wrong impression that the
uncore event doesn't work.

An uncore block could be composed by several PMUs. An uncore event alias
is a joint name which means the same event runs on all PMUs of a block.
Perf doesn't support mixed events from different PMUs in the same group.
It is wrong to put uncore event aliases in a big group.

The right way is to split the big group into multiple small groups which
only include the events from the same PMU.

Only uncore event aliases from the same uncore block should be specially
handled here. It doesn't make sense to mix the uncore events with other
uncore events from different blocks or even core events in a group.

With the patch:
  #           time             counts unit events
     1.001557653            140,833      unc_m_cas_count.all
     1.001557653      1,330,231,332      unc_m_clockticks
     2.002709483             85,007      unc_m_cas_count.all
     2.002709483      1,429,494,563      unc_m_clockticks

Reported-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Agustin Vega-Frias <agustinv@codeaurora.org>
Cc: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shaokun Zhang <zhangshaokun@hisilicon.com>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1525727623-19768-1-git-send-email-kan.liang@linux.intel.com


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