x86: bpf_jit_comp: add vlan tag support

This patch is a follow-up for patch "net: filter: add vlan tag access"
to support the new VLAN_TAG/VLAN_TAG_PRESENT accessors in BPF JIT.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ani Sinha <ani@aristanetworks.com>
Cc: Daniel Borkmann <danborkmann@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>