perf trace: Add augmenter for clock_gettime's rqtp timespec arg

One more before going the BTF way:

  # perf trace -e /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o,*nanosleep
         ? pool-gsd-smart/2893  ... [continued]: clock_nanosleep())    = 0
         ? gpm/1042  ... [continued]: clock_nanosleep())    = 0
     1.232 pool-gsd-smart/2893 clock_nanosleep(rqtp: { .tv_sec: 1, .tv_nsec: 0 }, rmtp: 0x7f64d7ffec50) ...
     1.232 pool-gsd-smart/2893  ... [continued]: clock_nanosleep())    = 0
   327.329 gpm/1042 clock_nanosleep(rqtp: { .tv_sec: 2, .tv_nsec: 0 }, rmtp: 0x7ffddfd1cf20) ...
  1002.482 pool-gsd-smart/2893 clock_nanosleep(rqtp: { .tv_sec: 1, .tv_nsec: 0 }, rmtp: 0x7f64d7ffec50) = 0
   327.329 gpm/1042  ... [continued]: clock_nanosleep())    = 0
  2003.947 pool-gsd-smart/2893 clock_nanosleep(rqtp: { .tv_sec: 1, .tv_nsec: 0 }, rmtp: 0x7f64d7ffec50) ...
  2003.947 pool-gsd-smart/2893  ... [continued]: clock_nanosleep())    = 0
  2327.858 gpm/1042 clock_nanosleep(rqtp: { .tv_sec: 2, .tv_nsec: 0 }, rmtp: 0x7ffddfd1cf20) ...
         ? crond/1384  ... [continued]: clock_nanosleep())    = 0
  3005.382 pool-gsd-smart/2893 clock_nanosleep(rqtp: { .tv_sec: 1, .tv_nsec: 0 }, rmtp: 0x7f64d7ffec50) ...
  3005.382 pool-gsd-smart/2893  ... [continued]: clock_nanosleep())    = 0
  3675.633 crond/1384 clock_nanosleep(rqtp: { .tv_sec: 60, .tv_nsec: 0 }, rmtp: 0x7ffcc02b66b0) ...
^C#

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