perf tools: Remove some needless __maybe_unused

I.e. those parameters/functions _are_ used, so ditch that misleading attribute.

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-13cqtjh0yojg5gzvpq1zzpl0@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-report.c

@@ -648,7 +648,7 @@ report_parse_ignore_callees_opt(const struct option *opt __maybe_unused,
 }
 
 static int
-parse_branch_mode(const struct option *opt __maybe_unused,
+parse_branch_mode(const struct option *opt,
 		  const char *str __maybe_unused, int unset)
 {
 	int *branch_mode = opt->value;