Merge branch 'hns3-loopback-selftest'

Yunsheng Lin says:

====================
Add mac loopback selftest support in hns3 driver

This patchset refactors the skb receiving and transmitting function
before adding mac loopback selftest support in hns3 driver.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>