MFC of ether_input() changes

[Bruce M Simpson]

Actually, I thought the change which moved the VLAN tag out of the mbuf 
tag pool and into the mbuf packet header had also been MFCed. It has not.

As CURRENT is the branch normally used for feature development it is 
probably best I don't MFC this unless the VLAN tag change is MFCed also.

Therefore there is not a lot of point in merging this change apart from 
to benefit from the code cleanup which M_PROMISC offers, so I'll back 
off for now.

Cheers...
BMS