perf trace beauty: Export the strarrays scnprintf method

perf trace beauty: Export the strarrays scnprintf method

As we'll call it from the fcntl cmd scnprintf method, that needs to look
at the cmd to mask the next fcntl argument when it is ignored.

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-fzlvkhew5vbxefneuciihgbc@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>