IB/cma: Fix RDMA port validation for iWarp

cma_validate_port wrongly assumed that Ethernet devices are RoCE
devices and thus their ndev should be matched in the GID table.
This broke the iWarp support. Fixing that matching the ndev only if
we work on a RoCE port.

Cc: <stable@vger.kernel.org> # 4.4.x-
Fixes: abae1b71 ('IB/cma: cma_validate_port should verify the port
		     and netdevice')
Reported-by: Hariprasad Shenai <hariprasad@chelsio.com>
Tested-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/core/cma.c

@@ -551,7 +551,7 @@ static inline int cma_validate_port(struct ib_device *device, u8 port,
 	if ((dev_type != ARPHRD_INFINIBAND) && rdma_protocol_ib(device, port))
 		return ret;
 
-	if (dev_type == ARPHRD_ETHER) {
+	if (dev_type == ARPHRD_ETHER && rdma_protocol_roce(device, port)) {
 		ndev = dev_get_by_index(&init_net, bound_if_index);
 		if (ndev && ndev->flags & IFF_LOOPBACK) {
 			pr_info("detected loopback device\n");