RDMA/hns: Reorganize doorbell update interfaces for all queues

The doorbell update interfaces are very similar for different queues, such
as SQ, RQ, SRQ, CQ and EQ. So reorganize these code and also fix some
inappropriate naming.

Link: https://lore.kernel.org/r/1616840738-7866-3-git-send-email-liweihang@huawei.com
Signed-off-by: Yixian Liu <liuyixian@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>