net-next/hinic: Add management messages

Add the management messages for sending to api cmd and the asynchronous
event handler for the completion of the messages.

Signed-off-by: Aviad Krawczyk <aviad.krawczyk@huawei.com>
Signed-off-by: Zhao Chen <zhaochen6@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>