Move the related codes of creating user srq and kernel srq into two
independent functions as well as remove some unused code and
simplifications.

Link: https://lore.kernel.org/r/1562593285-8037-3-git-send-email-oulijun@huawei.comSigned-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>