perf env: Fix memory leak of cpu_pmu_caps

ASan reports memory leaks while running:

 # perf test "83: Zstd perf.data compression/decompression"

The first of the leaks is caused by env->cpu_pmu_caps not being freed.

This patch adds the missing (z)free inside perf_env__exit.
Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Fixes: 6f91ea28 ("perf header: Support CPU PMU capabilities")
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/6ba036a8220156ec1f3d6be3e5d25920f6145028.1626343282.git.rickyman7@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/env.c

@@ -191,6 +191,7 @@ void perf_env__exit(struct perf_env *env)
 	zfree(&env->sibling_threads);
 	zfree(&env->pmu_mappings);
 	zfree(&env->cpu);
+	zfree(&env->cpu_pmu_caps);
 	zfree(&env->numa_map);
 
 	for (i = 0; i < env->nr_numa_nodes; i++)