net: hns3: Add HNS3 IMP(Integrated Mgmt Proc) Cmd Interface Support

This patch adds the support of IMP (Integrated Management Processor)
command interface to the HNS3 driver.

Each PF/VF has support of CQP(Command Queue Pair) ring interface.
Each CQP consis of send queue CSQ and receive queue CRQ.
There are various commands a PF/VF may support, like for Flow Table
manipulation, Device management, Packet buffer allocation, Forwarding,
VLANs config, Tunneling/Overlays etc.

This patch contains code to initialize the command queue, manage the
command queue descriptors and Rx/Tx protocol with the command processor
in the form of various commands/results and acknowledgements.

Signed-off-by: Daode Huang <huangdaode@hisilicon.com>
Signed-off-by: lipeng <lipeng321@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: Yisen Zhuang <yisen.zhuang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>