perf trace: Beautify set_tid_address, getpid, getppid return values

Showing the COMM for that return, if available.

  # trace -e getpid,getppid,set_tid_address
    490.007 ( 0.005 ms): sh/8250 getpid(...) = 8250 (sh)
    490.014 ( 0.001 ms): sh/8250 getppid(...) = 7886 (make)
    491.156 ( 0.004 ms): install/8251 set_tid_address(tidptr: 0x7f204a9d4ad0) = 8251 (install)
  ^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-psbpplqupatom9x4uohbxid5@git.kernel.org


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