perf pmu: Use pmu_events table to create aliases

At run time (when 'perf' is starting up), locate the specific table of
PMU events that corresponds to the current CPU. Using that table, create
aliases for the each of the PMU events in the CPU. The use these aliases
to parse the user specified perf event.

In short this would allow the user to specify events using their aliases
rather than raw event codes.

Based on input and some earlier patches from Andi Kleen, Jiri Olsa.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1473978296-20712-4-git-send-email-sukadev@linux.vnet.ibm.com


[ Make pmu_add_cpu_aliases() return void, since it was returning just '0' and
  furthermore, even that was being discarded via an explicit (void) cast ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>