RDMA/hns: Optimize post and poll process

Add unlikely() and likely() to optimize main I/O process code.

Link: https://lore.kernel.org/r/1589982799-28728-4-git-send-email-liweihang@huawei.com


Signed-off-by: Lang Cheng <chenglang@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>