From: Phil Sutter <phil@nwl.cc>
Date: Fri,  2 Aug 2013 11:37:40 +0200

Since tpacket_fill_skb() parses the protocol field in ethernet frames'
headers, it's easy to see if any passed frame is a VLAN one and account
for the extended size.

But as the real protocol does not turn up before tpacket_fill_skb()
runs which in turn also checks the frame length, move the max frame
length calculation into the function.

Signed-off-by: Phil Sutter <phil@nwl.cc>

Applied.