perf tools: Add aux_output attribute flag

perf tools: Add aux_output attribute flag

Add aux_output attribute flag to match the kernel's perf_event.h file.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190806084606.4021-4-alexander.shishkin@linux.intel.com
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>