net: hns3: add stats logging when skb padding fails

skb_put_padto() may fails because of memory failure, sw_err_cnt
is already used to log memory failure in hns3_skb_linearize(),
so use it to log the memory failure for skb_put_padto() too.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>