net: hns3: Drop depricated mta table support

For mta table support has been dropped, remove the code for mta table.

Signed-off-by: Zhongzhu Liu <liuzhongzhu@huawei.com>
Signed-off-by: Jian Shen <shenjian15@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>