RDMA/hns: Clear extended doorbell info before using

Both of HIP08 and HIP09 require the extended doorbell information to be
cleared before being used.

Fixes: 6b63597d

 ("RDMA/hns: Add TSQ link table support")
Link: https://lore.kernel.org/r/1623392089-35639-1-git-send-email-liweihang@huawei.com
Signed-off-by: Xi Wang <wangxi11@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>