RDMA/core: Clarify rdma_ah_find_type

iWARP does not use rdma_ah_attr_type, and for this reason we do not have a
RDMA_AH_ATTR_TYPE_IWARP. rdma_ah_find_type should not even be called on iwarp
ports and for clarity it shouldn't have a special test for iWarp.

This changes the result from RDMA_AH_ATTR_TYPE_ROCE to RDMA_AH_ATTR_TYPE_IB
when wrongly called on an iWarp port.

Fixes: 44c58487 ("IB/core: Define 'ib' and 'roce' rdma_ah_attr types")
Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>