net: wan: add necessary () to macro argument

Macro argument 'card' and 'port' may be better as
'(card)' and '(port)' to avoid precedence issues.

Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>