perf tools: Check mem-loads auxiliary event

perf tools: Check mem-loads auxiliary event

For some platforms, an auxiliary event has to be enabled
simultaneously with the load latency event.

For Alderlake, the auxiliary event is created in "cpu_core" pmu.

So first we need to check the existing of "cpu_core" pmu
and then check if this pmu has auxiliary event.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210527001610.10553-2-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>