NIC vlan(4) capabilities
This updates the drivers equipped to do hardware VLAN support to
announce the fact. This is already done by em(4) and re(4) and allows
control of the features via ifconfig. Capabilities were checked against
FreeBSD and the respective man pages.
Is it worth setting IFCAP_VLAN_MTU in dc(4), fxp(4), sis(4), ste(4) and
tx(4) as they are documented as supporting long frames for vlan natively?