Fix printing of invalid flags argument of perf_event_open syscall

* numa.c (SYS_FUNC(perf_event_open)): Print 5th argument of syscall
using printflags_long.
diff --git a/perf.c b/perf.c
index f91b9d3..8ab58a0 100644
--- a/perf.c
+++ b/perf.c
@@ -41,7 +41,7 @@
 		(int) tcp->u_arg[1],
 		(int) tcp->u_arg[2],
 		(int) tcp->u_arg[3]);
-	printflags(perf_event_open_flags, tcp->u_arg[4], "PERF_FLAG_???");
+	printflags_long(perf_event_open_flags, tcp->u_arg[4], "PERF_FLAG_???");
 
 	return RVAL_DECODED | RVAL_FD;
 }