tools lib traceevent: Fix conversion of pointer to integer of different size

gcc complaint on 32-bit system:

  /home/acme/git/linux/tools/lib/traceevent/event-parse.c: In function ‘eval_num_arg’:
  /home/acme/git/linux/tools/lib/traceevent/event-parse.c:3468:9: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]

This is because the eval_num_arg returns everything as an 'unsigned long long',
so it converts a void pointer to a wider integer, fix it by converting the void
pointer to an integer of the same size, 'unsigned long', before casting it to
'unsigned long long'.
Acked-by: Steven Rostedt <rostedt@goodmis.org>
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: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-yllx4aqcg06v5n4vjpwiiuld@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/traceevent/event-parse.c

@@ -3465,7 +3465,7 @@ eval_num_arg(void *data, int size, struct event_format *event, struct print_arg
 		 * is in the bottom half of the 32 bit field.
 		 */
 		offset &= 0xffff;
-		val = (unsigned long long)(data + offset);
+		val = (unsigned long long)((unsigned long)data + offset);
 		break;
 	default: /* not sure what to do there */
 		return 0;