perf tools: Remove unused 'prefix' from builtin functions

We got it from the git sources but never used it for anything, with the
place where this would be somehow used remaining:

  static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
  {
	prefix = NULL;
	if (p->option & RUN_SETUP)
		prefix = NULL; /* setup_perf_directory(); */

Ditch it.

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: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-uw5swz05vol0qpr32c5lpvus@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index b92c4d9..79833e2 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -3272,10 +3272,10 @@ static int __cmd_record(int argc, const char **argv)
 
 	BUG_ON(i != rec_argc);
 
-	return cmd_record(i, rec_argv, NULL);
+	return cmd_record(i, rec_argv);
 }
 
-int cmd_sched(int argc, const char **argv, const char *prefix __maybe_unused)
+int cmd_sched(int argc, const char **argv)
 {
 	const char default_sort_order[] = "avg, max, switch, runtime";
 	struct perf_sched sched = {
@@ -3412,7 +3412,7 @@ int cmd_sched(int argc, const char **argv, const char *prefix __maybe_unused)
 	 * Aliased to 'perf script' for now:
 	 */
 	if (!strcmp(argv[0], "script"))
-		return cmd_script(argc, argv, prefix);
+		return cmd_script(argc, argv);
 
 	if (!strncmp(argv[0], "rec", 3)) {
 		return __cmd_record(argc, argv);