ubifs: tnc: use monotonic znode timestamp

The tnc uses get_seconds() based timestamps to check the age of a znode,
which has two problems: on 32-bit architectures this may overflow in
2038 or 2106, and it gives incorrect information when the system time
is updated using settimeofday().

Using montonic timestamps with ktime_get_seconds() solves both thes
problems.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
diff --git a/fs/ubifs/shrinker.c b/fs/ubifs/shrinker.c
index 9a9fb94..9d10cbd 100644
--- a/fs/ubifs/shrinker.c
+++ b/fs/ubifs/shrinker.c
@@ -71,7 +71,7 @@ static int shrink_tnc(struct ubifs_info *c, int nr, int age, int *contention)
 {
 	int total_freed = 0;
 	struct ubifs_znode *znode, *zprev;
-	int time = get_seconds();
+	time64_t time = ktime_get_seconds();
 
 	ubifs_assert(mutex_is_locked(&c->umount_mutex));
 	ubifs_assert(mutex_is_locked(&c->tnc_mutex));