perf tools: Add PMU configuration to tools

Now that the required mechanic is there to deal with PMU specific
configuration, add the functionality to the tools where events can be
selected.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1474041004-13956-7-git-send-email-mathieu.poirier@linaro.org


[ Fix the build on XSI-compliant systems, using str_error_r() to make sure we return a string, not an integer ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>