y2038: lib/cobalt/mutex: dispatch mutex_timedlock

In case the libc in use reports a 64 bit time_t dispacht
mutex_timedlock to the kernel entry point that accepts it.
Signed-off-by: Song Chen <chensong_2000@189.cn>
Signed-off-by: Florian Bezdeka <florian.bezdeka@siemens.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

lib/cobalt/mutex.c

@@ -479,7 +479,11 @@ slow_path:
 	}
 
 	do {
+#ifdef __USE_TIME_BITS64
+		ret = XENOMAI_SYSCALL2(sc_cobalt_mutex_timedlock64, _mutex, to);
+#else
 		ret = XENOMAI_SYSCALL2(sc_cobalt_mutex_timedlock, _mutex, to);
+#endif
 	} while (ret == -EINTR);
 
 	if (ret == 0)