IB/mlx5: Refactor raw packet QP modify function

Added a struct for modifying raw QP, this will allow modifying
multiple parameters in raw packet QP RQ and can also be used for
SQ in the future.

Signed-off-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
