net/hns3: add VLAN configuration compatibility

net/hns3: add VLAN configuration compatibility

Because of hardware limitation based on the old version of hns3 network
engine, there are some restrictions:
a) HNS3 PMD driver needs select different processing mode for VLAN based
   on whether PVID is set which means our driver need sense the PVID
   states.
b) For packets transmitting process, only two layer of VLAN tag is
   supported. If the total number of VLAN tags in mbuf and VLAN offload
   by hardware (VLAN insert by descriptor) exceeds two, the VLAN in mbuf
   will be overwritten by VLAN in the descriptor.
c) If port based VLAN is set, only one VLAN header is allowed in mbuf or
   it will be discard by hardware.

In order to solve these restriction, two change is implemented on the
new versions of network engine.
1) add a new VLAN tagged insertion mode, named tag shift mode;
2) add a new VLAN strip control bit, named strip hide enable;

The tag shift mode means that VLAN tag will shift automatically when the
inserted place has a tag. For PMD driver, the VLAN tag1 and tag2
configurations in Tx side do not need to be considered because the
hardware completes it. However, the related configuration will still be
retained to be compatible with the old version of network engine.

The VLAN strip hide means that hardware will strip the VLAN tag and hide
VLAN in descriptor (VLAN ID exposed as zero and related STRIP_TAGP is
off).

These changes make it no longer necessary for the hns3 PMD driver to be
aware of the PVID status and have the ability to send mult-layer (more
than two) VLANs packets. Therefore, hns3 PMD driver introduces the
concept of VLAN mode and adds a new VLAN mode named HNS3_PVID_MODE to
indicate that PVID-related IO process can be implemented by the
hardware. And VF driver does not need to be modified because the related
mailbox messages will not be sent by PF kernel mode netdev driver under
new network engine and all the related hardware configuration is on the
PF side.

Signed-off-by: Chengchang Tang <tangchengchang@huawei.com>
Signed-off-by: Wei Hu (Xavier) <xavier.huwei@huawei.com>