net: hns3: Add HNS3 VF IMP(Integrated Management Proc) cmd interface

This patch adds support of command interface for communication with
the IMP(Integrated Management Processor) for HNS3 Virtual Function
Driver.

Each 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 VF may support, like to query frimware
version, TQP management, statistics, interrupt related, mailbox etc.

This also 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: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: lipeng <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>