[VLAN]: Avoid expensive divides

We can avoid divides (as seen with CONFIG_CC_OPTIMIZE_FOR_SIZE=y on
x86) changing vlan_group_get_device()/vlan_group_set_device() id
parameter from signed to unsigned.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/linux/if_vlan.h

@@ -81,14 +81,16 @@ struct vlan_group {
 	struct rcu_head		rcu;
 };
 
-static inline struct net_device *vlan_group_get_device(struct vlan_group *vg, int vlan_id)
+static inline struct net_device *vlan_group_get_device(struct vlan_group *vg,
+						       unsigned int vlan_id)
 {
 	struct net_device **array;
 	array = vg->vlan_devices_arrays[vlan_id / VLAN_GROUP_ARRAY_PART_LEN];
 	return array[vlan_id % VLAN_GROUP_ARRAY_PART_LEN];
 }
 
-static inline void vlan_group_set_device(struct vlan_group *vg, int vlan_id,
+static inline void vlan_group_set_device(struct vlan_group *vg,
+					 unsigned int vlan_id,
 					 struct net_device *dev)
 {
 	struct net_device **array;