macvlan: remove redundant null check on data

Because macvlan_common_newlink() and macvlan_changelink() already
checked NULL data parameter, so the additional check is unnecessary,
just remove it.

Fixes: 79cf79a ("macvlan: add source mode")
Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/macvlan.c

@@ -1385,7 +1385,7 @@ static int macvlan_changelink_sources(struct macvlan_dev *vlan, u32 mode,
 				return ret;
 		}
 
-		if (!data || !data[IFLA_MACVLAN_MACADDR_DATA])
+		if (!data[IFLA_MACVLAN_MACADDR_DATA])
 			return 0;
 
 		head = nla_data(data[IFLA_MACVLAN_MACADDR_DATA]);