RDMA/hns: Remove unnecessary ret variable from hns_roce_dereg_mr()

Fix the following coccicheck warning:

drivers/infiniband/hw/hns/hns_roce_mr.c:343:5-8: Unneeded variable: "ret".

Return 0 directly instead.

Link: https://lore.kernel.org/r/20220426070858.9098-1-guozhengkui@vivo.comSigned-off-by: Guo Zhengkui <guozhengkui@vivo.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/hns/hns_roce_mr.c

@@ -340,7 +340,6 @@ int hns_roce_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata)
 {
 	struct hns_roce_dev *hr_dev = to_hr_dev(ibmr->device);
 	struct hns_roce_mr *mr = to_hr_mr(ibmr);
-	int ret = 0;
 
 	if (hr_dev->hw->dereg_mr)
 		hr_dev->hw->dereg_mr(hr_dev);
@@ -348,7 +347,7 @@ int hns_roce_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata)
 	hns_roce_mr_free(hr_dev, mr);
 	kfree(mr);
 
-	return ret;
+	return 0;
 }
 
 struct ib_mr *hns_roce_alloc_mr(struct ib_pd *pd, enum ib_mr_type mr_type,