RDMA/cma: Remove NULL check before dev_{put, hold}

The call netdev_{put, hold} of dev_{put, hold} will check NULL,
so there is no need to check before using dev_{put, hold},
remove it to silence the warnings:

./drivers/infiniband/core/cma.c:713:2-9: WARNING: NULL check before dev_{put, hold} functions is not needed.
./drivers/infiniband/core/cma.c:2433:2-9: WARNING: NULL check before dev_{put, hold} functions is not needed.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=4668Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Link: https://lore.kernel.org/r/20230331010633.63261-1-yang.lee@linux.alibaba.comSigned-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/core/cma.c

@@ -710,8 +710,7 @@ cma_validate_port(struct ib_device *device, u32 port,
 	}
 
 	sgid_attr = rdma_find_gid_by_port(device, gid, gid_type, port, ndev);
-	if (ndev)
-		dev_put(ndev);
+	dev_put(ndev);
 	return sgid_attr;
 }
 
@@ -2430,8 +2429,7 @@ static int cma_ib_req_handler(struct ib_cm_id *cm_id,
 	mutex_unlock(&listen_id->handler_mutex);
 
 net_dev_put:
-	if (net_dev)
-		dev_put(net_dev);
+	dev_put(net_dev);
 
 	return ret;
 }