can: gw: use kmem_cache_free() instead of kfree()

Memory allocated by kmem_cache_alloc() should be freed using
kmem_cache_free(), not kfree().

Cc: linux-stable <stable@vger.kernel.org> # >= v3.2
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

net/can/gw.c

@@ -466,7 +466,7 @@ static int cgw_notifier(struct notifier_block *nb,
 			if (gwj->src.dev == dev || gwj->dst.dev == dev) {
 				hlist_del(&gwj->list);
 				cgw_unregister_filter(gwj);
-				kfree(gwj);
+				kmem_cache_free(cgw_cache, gwj);
 			}
 		}
 	}
@@ -864,7 +864,7 @@ static void cgw_remove_all_jobs(void)
 	hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) {
 		hlist_del(&gwj->list);
 		cgw_unregister_filter(gwj);
-		kfree(gwj);
+		kmem_cache_free(cgw_cache, gwj);
 	}
 }
 
@@ -920,7 +920,7 @@ static int cgw_remove_job(struct sk_buff *skb,  struct nlmsghdr *nlh, void *arg)
 
 		hlist_del(&gwj->list);
 		cgw_unregister_filter(gwj);
-		kfree(gwj);
+		kmem_cache_free(cgw_cache, gwj);
 		err = 0;
 		break;
 	}