net: hns: fix sbm default parameters config error

The default sbm config parameter leaves little buffer when there is heavy
traffic, which will cause packets drop. This patch changes them to make
enough buffers for handling packets.

Signed-off-by: Daode Huang <huangdaode@hisilicon.com>
Signed-off-by: Yisen Zhuang <Yisen.Zhuang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>