perf metricgroup: Fix metricgroup__has_metric_or_groups()

perf metricgroup: Fix metricgroup__has_metric_or_groups()

Use metricgroup__for_each_metric() rather than
pmu_metrics_table__for_each_metric() that combines the
default metric table with, a potentially empty, CPUID table.

Fixes: cee275edcdb1acfd ("perf metricgroup: Don't early exit if no CPUID table exists")
Reviewed-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Cc: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>