NTB: ntb_transport: fix possible memory leak while device_register() fails

If device_register() returns error, the name allocated by
dev_set_name() need be freed. As comment of device_register()
says, it should use put_device() to give up the reference in
the error path. So fix this by calling put_device(), then the
name can be freed in kobject_cleanup(), and client_dev is freed
in ntb_transport_client_release().

Fixes: fce8a7bb

 ("PCI-Express Non-Transparent Bridge Support")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>