RDMA/hns: Fix PBL page MTR find

RDMA/hns: Fix PBL page MTR find

[ Upstream commit 9fb39ef2ff3e18f1740625ba04093dfbef086d2b ]

Now, The address of the first two pages in the MR will be searched, which
use to speed up the lookup of the pbl table for hardware.  An exception
will occur when there is only one page in this MR.  This patch fix the
number of page to search.

Fixes: 9b2cf76c9f05 ("RDMA/hns: Optimize PBL buffer allocation process")
Link: https://lore.kernel.org/r/20221126102911.2921820-4-xuhaoyue1@hisilicon.com
Signed-off-by: Chengchang Tang <tangchengchang@huawei.com>
Signed-off-by: Haoyue Xu <xuhaoyue1@hisilicon.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>