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>