perf scripting perl: Fix build error on Fedora 12

Cast __u64 to u64 to silence this warning on older distros, such as
Fedora 12:

    CC       /tmp/build/perf/util/scripting-engines/trace-event-perl.o
  cc1: warnings being treated as errors
  util/scripting-engines/trace-event-perl.c: In function ‘perl_process_tracepoint’:
  util/scripting-engines/trace-event-perl.c:285: error: format ‘%lu’ expects type ‘long unsigned int’, but argument 2 has type ‘__u64’
  make[1]: *** [/tmp/build/perf/util/scripting-engines/trace-event-perl.o] Error 1
  make: *** [install] Error 2
  make: Leaving directory `/home/acme/git/linux/tools/perf'
  [acme@fedora12 linux]$

Reported-by: Waiman Long <Waiman.Long@hp.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Waiman Long <Waiman.Long@hp.com>
Link: http://lkml.kernel.org/n/tip-nlxofdqcdjfm0w9o6bgq4kqv@git.kernel.org
Link: http://lkml.kernel.org/r/1381265120-58532-1-git-send-email-Waiman.Long@hp.com


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