RDMA/rxe: Add ib_device_get_by_name() and use it in rxe

rxe has an open coded version of this that is not as safe as the core
version. This lets us eliminate the internal device list entirely from
rxe.

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

drivers/infiniband/sw/rxe/rxe.c

@@ -69,8 +69,6 @@ void rxe_dealloc(struct ib_device *ib_dev)
 
 	if (rxe->tfm)
 		crypto_free_shash(rxe->tfm);
-
-	list_del(&rxe->list);
 }
 
 /* initialize rxe device parameters */
@@ -275,7 +273,6 @@ static int rxe_init(struct rxe_dev *rxe)
 	spin_lock_init(&rxe->mmap_offset_lock);
 	spin_lock_init(&rxe->pending_lock);
 	INIT_LIST_HEAD(&rxe->pending_mmaps);
-	INIT_LIST_HEAD(&rxe->list);
 
 	mutex_init(&rxe->usdev_lock);