IB/uverbs: Make use of ib_modify_qp variant to avoid resolving DMAC

This patch makes use of IB core's ib_modify_qp_with_udata function that
also resolves the DMAC and handles udata.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Eli Cohen <eli@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>