src: Fix dumping vlan rules

src: Fix dumping vlan rules

Given the following bridge rules:
1. ip protocol icmp accept
2. ether type vlan vlan type ip ip protocol icmp accept

The are currently both dumped by "nft list ruleset" as
1. ip protocol icmp accept
2. ip protocol icmp accept

Though, the netlink code actually is different

bridge filter FORWARD 4
  [ payload load 2b @ link header + 12 => reg 1 ]
  [ cmp eq reg 1 0x00000008 ]
  [ payload load 1b @ network header + 9 => reg 1 ]
  [ cmp eq reg 1 0x00000001 ]
  [ immediate reg 0 accept ]

bridge filter FORWARD 5 4
  [ payload load 2b @ link header + 12 => reg 1 ]
  [ cmp eq reg 1 0x00000081 ]
  [ payload load 2b @ link header + 16 => reg 1 ]
  [ cmp eq reg 1 0x00000008 ]
  [ payload load 1b @ network header + 9 => reg 1 ]
  [ cmp eq reg 1 0x00000001 ]
  [ immediate reg 0 accept ]

What happens here is that:

1. vlan type ip kills ether type vlan
2. ip protocol icmp kills vlan type ip

Fix this by avoiding the removal of all vlan statements
in the given example.

Signed-off-by: Michael Braun <michael-dev@fami-braun.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>