!2055 Only enable unicast promisc when mac table full to fix the hns3 bug

Merge Pull Request from: @svishen 
 
This patch fix enable unicast promisc for the function once configure mac address fail, only enable unicast promisc when mac table full

issue:
https://gitee.com/openeuler/kernel/issues/I7Z434 
 
Link:https://gitee.com/openeuler/kernel/pulls/2055

 

Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>