perf trace: Allow configuring if the syscall start timestamp should be printed

  # trace -e open*,close,*sleep sleep 1
     0.000 openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC           ) = 3
     0.016 close(fd: 3                                                           ) = 0
     0.024 openat(dfd: CWD, filename: /lib64/libc.so.6, flags: CLOEXEC           ) = 3
     0.074 close(fd: 3                                                           ) = 0
     0.235 openat(dfd: CWD, filename: /usr/lib/locale/locale-archive, flags: CLOEXEC) = 3
     0.251 close(fd: 3                                                           ) = 0
     0.285 nanosleep(rqtp: 0x7ffd68e6d620, rmtp: 0                               ) = 0
  1000.386 close(fd: 1                                                           ) = 0
  1000.395 close(fd: 2                                                           ) = 0
  #

  # perf config trace.show_timestamp=no
  # trace -e open*,close,*sleep sleep 1
  openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC           ) = 3
  close(fd: 3                                                           ) = 0
  openat(dfd: CWD, filename: /lib64/libc.so.6, flags: CLOEXEC           ) = 3
  close(fd: 3                                                           ) = 0
  openat(dfd: CWD, filename: , flags: CLOEXEC                           ) = 3
  close(fd: 3                                                           ) = 0
  nanosleep(rqtp: 0x7fffa79c38e0, rmtp: 0                               ) = 0
  close(fd: 1                                                           ) = 0
  close(fd: 2                                                           ) = 0
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-mjjnicy48367jah6ls4k0nk8@git.kernel.org


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