perf config: Call perf_config__init() lazily

We check what perf_config__init() does at each perf_config() call,
namely if the static perf_config instance was created, so instead of
bailing out in that case, try to allocate it, bailing if it fails.

Now to get the perf_config() call out of the start of perf's main()
function, doing it also lazily.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Taeung Song <treeze.taeung@gmail.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-4bo45k6ivsmbxpfpdte4orsg@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/perf.c

@@ -458,7 +458,6 @@ int main(int argc, const char **argv)
 
 	srandom(time(NULL));
 
-	perf_config__init();
 	err = perf_config(perf_default_config, NULL);
 	if (err)
 		return err;