IB/cma: Use rdma_protocol_roce() and remove cma_protocol_roce_dev_port()

rdma_protocol_roce() API from the ib_core already provides a way to
detect whether a given device+port is RoCE or not.
Therefore, make use of it and avoid implementing it again in rdmacm
module.

Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>