perf tools: Fix a compiling error in trace-event-perl.c for 32 bits machine

On my x86_32 mahcine, there is a compile error:

        CC 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
	expects type 'int', but argument 2 has type '__u64'
        make: *** [util/scripting-engines/trace-event-perl.o] Error 1

Fix it by using the "%PRIu64" for __u64.

v2: use PRIu64 as suggested by Arnaldo.

Signed-off-by: Feng Tang <feng.tang@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120828101730.6b2fd97e@feng-i7


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