perf trace: Beautify linux specific fcntl commands

We were only beautifying (transforming from an integer to its name) the
non-linux specific fcntl syscall cmd args, fix it:

Before:

  # perf trace -e fcntl -p 2472
     0.000 ( 0.017 ms): gnome-terminal/2472 fcntl(fd: 55, cmd: 1030) = 56
  ^C#

After:

  # trace -e fcntl -p 2472
     0.000 ( 0.015 ms): gnome-terminal/2472 fcntl(fd: 55, cmd: DUPFD_CLOEXEC) = 56
  ^C#

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-zigsxruk4wbfn8iylboy9wzo@git.kernel.org


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