Moves the related code of creating cq into separate functions in order to
improve comprehensibility.

Link: https://lore.kernel.org/r/1562593285-8037-2-git-send-email-oulijun@huawei.comSigned-off-by: NLijun Ou <oulijun@huawei.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>