net: bridge: vlan: fix memory leak in __allowed_ingress

When using per-vlan state, if vlan snooping and stats are disabled,
untagged or priority-tagged ingress frame will go to check pvid state.
If the port state is forwarding and the pvid state is not
learning/forwarding, untagged or priority-tagged frame will be dropped
but skb memory is not freed.
Should free skb when __allowed_ingress returns false.

Fixes: a580c76 ("net: bridge: vlan: add per-vlan state")
Signed-off-by: Tim Yi <tim.yi@pica8.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Link: https://lore.kernel.org/r/20220127074953.12632-1-tim.yi@pica8.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/bridge/br_vlan.c

@@ -560,10 +560,10 @@ static bool __allowed_ingress(const struct net_bridge *br,
 		    !br_opt_get(br, BROPT_VLAN_STATS_ENABLED)) {
 			if (*state == BR_STATE_FORWARDING) {
 				*state = br_vlan_get_pvid_state(vg);
-				return br_vlan_state_allowed(*state, true);
-			} else {
-				return true;
+				if (!br_vlan_state_allowed(*state, true))
+					goto drop;
 			}
+			return true;
 		}
 	}
 	v = br_vlan_find(vg, *vid);