rust: Add time_namespace helpers

Signed-off-by: Asahi Lina <lina@asahilina.net>

Author: hoshinolina

rust/helpers/helpers.c

@@ -34,6 +34,7 @@
 #include "slab.c"
 #include "spinlock.c"
 #include "task.c"
+#include "time_namespace.c"
 #include "timekeeping.c"
 #include "uaccess.c"
 #include "wait.c"

rust/helpers/time_namespace.c

@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/time_namespace.h>
+
+void rust_helper_timens_add_monotonic(struct timespec64 *ts) {
+	timens_add_monotonic(ts);
+}