perf evlist: Use the right prefix for 'struct evlist' diff methods

perf_evlist__ is for 'struct perf_evlist' methods, in tools/lib/perf/,
go on completing this split.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-diff.c

@@ -494,7 +494,7 @@ static struct evsel *evsel_match(struct evsel *evsel,
 	return NULL;
 }
 
-static void perf_evlist__collapse_resort(struct evlist *evlist)
+static void evlist__collapse_resort(struct evlist *evlist)
 {
 	struct evsel *evsel;
 
@@ -1214,7 +1214,7 @@ static int __cmd_diff(void)
 			goto out_delete;
 		}
 
-		perf_evlist__collapse_resort(d->session->evlist);
+		evlist__collapse_resort(d->session->evlist);
 
 		if (pdiff.ptime_range)
 			zfree(&pdiff.ptime_range);