ipvlan: Remove a useless comparison

Fix following gcc warning:

drivers/net/ipvlan/ipvlan_main.c:543:12: warning:
 comparison is always false due to limited range of data type [-Wtype-limits]

'mode' is a u16 variable, IPVLAN_MODE_L2 is zero,
the comparison is always false
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ipvlan/ipvlan_main.c

@@ -540,7 +540,7 @@ static int ipvlan_nl_validate(struct nlattr *tb[], struct nlattr *data[],
 	if (data[IFLA_IPVLAN_MODE]) {
 		u16 mode = nla_get_u16(data[IFLA_IPVLAN_MODE]);
 
-		if (mode < IPVLAN_MODE_L2 || mode >= IPVLAN_MODE_MAX)
+		if (mode >= IPVLAN_MODE_MAX)
 			return -EINVAL;
 	}
 	if (data[IFLA_IPVLAN_FLAGS]) {