net: return correct error code

stable inclusion
from stable-v5.10.84
commit 3fc88660ede60a5f6a7a8bf48efe6f5bfaae6cb1
bugzilla: 186030 https://gitee.com/openeuler/kernel/issues/I4QV2F

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3fc88660ede60a5f6a7a8bf48efe6f5bfaae6cb1

--------------------------------

[ Upstream commit 6def4801 ]

When kmemdup called failed and register_net_sysctl return NULL, should
return ENOMEM instead of ENOBUFS
Signed-off-by: Nliuguoqiang <liuguoqiang@uniontech.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

net/ipv4/devinet.c

@@ -2582,7 +2582,7 @@ static int __devinet_sysctl_register(struct net *net, char *dev_name,
 free:
 	kfree(t);
 out:
-	return -ENOBUFS;
+	return -ENOMEM;
 }
 
 static void __devinet_sysctl_unregister(struct net *net,