RDMA/mlx5: Directly compute the PAS list for raw QP RQ's

The RQ WQ created when making a raw ethernet QP copies the PAS list from
a dummy QPC command created earlier in the flow. The WQC and QPC PAS lists
are not fully compatible as the page_offset is a different size.

Create the RQ WQ's PAS list directly and do not try to copy it from
another command structure.

Like the prior patch, this also means that badly aligned buffers were not
correctly rejected.

Link: https://lore.kernel.org/r/20201115114311.136250-4-leon@kernel.org


Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>