dn_route: replace "jiffies-now>0" with "jiffies!=now"

Use "jiffies != now" to replace "jiffies - now > 0" to make
code more readable. We want to put a limit on how long the
loop can run for before rescheduling.
Signed-off-by: Yu Zhe <yuzhe@nfschina.com>
Link: https://lore.kernel.org/r/20220729061712.22666-1-yuzhe@nfschina.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/decnet/dn_route.c

@@ -201,7 +201,7 @@ static void dn_dst_check_expire(struct timer_list *unused)
 		}
 		spin_unlock(&dn_rt_hash_table[i].lock);
 
-		if ((jiffies - now) > 0)
+		if (jiffies != now)
 			break;
 	}