!381 net: hns3: add support handling tx dhcp packets for ROH

Merge Pull Request from: @chenke1978 
 
[Description]
For ROH distributed scenario, EID is allocated by DHCP mode.
Driver needs to convert the origin MAC address to EID format,
and updates the destination MAC, chaddr and client id(if exists)
when transmit DHCP packets. Meantime, the chaddr field should
follow the source mac address, in order to make the dhcp
server reply to the right client. For the payload of
dhcp packet changed, so the checksum of L4 should be
calculated too.

[Testing]
kernel options:
CONFIG_ROH=m
CONFIG_ROH_HNS=m

Test passed with below step:
1. Load the NIC/ROCE/ROH driver normally on the ROH device.
2. Preparing the DHCP Server and DHCP Client applications
3. Enable the DHCP service on the server node.
4. Execute the DHCP client application on the client node.
5. Check the DHCP process and wait until the DHCP IP address
   allocation is complete.
6. The communication is normal based on the new IP address.

    
 
Link:https://gitee.com/openeuler/kernel/pulls/381

 

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