RDMA: Clean structures from CONFIG_INFINIBAND_ON_DEMAND_PAGING

CONFIG_INFINIBAND_ON_DEMAND_PAGING is used in general structures to
micro-optimize the memory footprint. Remove it, so it will allow us to
simplify various ODP device flows.

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