ext4: use ktime_get_real_seconds for i_dtime

We only care about the low 32-bit for i_dtime as explained in commit
b5f51573 ("ext4: avoid Y2038 overflow in recently_deleted()"), so
the use of get_seconds() is correct here, but that function is getting
removed in the process of the y2038 fixes, so let's use the modern
ktime_get_real_seconds() here.
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/inode.c

@@ -317,7 +317,7 @@ void ext4_evict_inode(struct inode *inode)
 	 * (Well, we could do this if we need to, but heck - it works)
 	 */
 	ext4_orphan_del(handle, inode);
-	EXT4_I(inode)->i_dtime	= get_seconds();
+	EXT4_I(inode)->i_dtime	= (__u32)ktime_get_real_seconds();
 
 	/*
 	 * One subtle ordering requirement: if anything has gone wrong