net: sched: Return the correct errno code

When kalloc or kmemdup failed, should return ENOMEM rather than ENOBUF.
Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Link: https://lore.kernel.org/r/20210204073950.18372-1-zhengyongjun3@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/sched/em_nbyte.c

@@ -31,7 +31,7 @@ static int em_nbyte_change(struct net *net, void *data, int data_len,
 	em->datalen = sizeof(*nbyte) + nbyte->len;
 	em->data = (unsigned long)kmemdup(data, em->datalen, GFP_KERNEL);
 	if (em->data == 0UL)
-		return -ENOBUFS;
+		return -ENOMEM;
 
 	return 0;
 }