NFC: fix possible resource leak

stable inclusion
from stable-5.10.13
commit 5a48918811c82aa9693b216bd3065aa0762ed222
bugzilla: 47995

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

commit d8f923c3 upstream.

Put the device to avoid resource leak on path that the polling flag is
invalid.

Fixes: a831b913 ("NFC: Do not return EBUSY when stopping a poll that's already stopped")
Signed-off-by: NPan Bian <bianpan2016@163.com>
Link: https://lore.kernel.org/r/20210121153745.122184-1-bianpan2016@163.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

net/nfc/netlink.c

@@ -852,6 +852,7 @@ static int nfc_genl_stop_poll(struct sk_buff *skb, struct genl_info *info)
 
 	if (!dev->polling) {
 		device_unlock(&dev->dev);
+		nfc_put_device(dev);
 		return -EINVAL;
 	}