RDMA/cxgb4: Don't free chunk that we have failed to allocate

In the error path of registering memory when there's a failure to
allocate a chunk from the memory pool, we try to free the same chunk
we just failed to allocate, which will BUG().

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/cxgb4/mem.c

@@ -468,7 +468,7 @@ struct ib_mr *c4iw_register_phys_mem(struct ib_pd *pd,
 	ret = alloc_pbl(mhp, npages);
 	if (ret) {
 		kfree(page_list);
-		goto err_pbl;
+		goto err;
 	}
 
 	ret = write_pbl(&mhp->rhp->rdev, page_list, mhp->attr.pbl_addr,