Hi Jeff,

attached is the promised cleanup of the vlan handling:
By default, the DP83815/6 nics reject packets larger than 1518 bytes. 
This must be disabled by setting the RxAcceptLong flag, otherwise vlan 
doesn't work. This is now properly implemented.

The patch also adds support for larger than normal frames: the nic can 
support up to 2046 byte frames, i.e. mtu 2024. I've tested mtu 2000 
between two natsemi nics: tcp bandwidth up from 11.7 to 11.9 MB/sec.
Additionally, it fixes a bug in the tx overrun handling: The drain 
threshold must be limited to 1472 bytes, larger settings are documented 
to cause internal nic corruptions.

Jeff, could you apply it to your tree and forward it?

Signed-Off-By: Manfred Spraul <manfred@colorfullife.com>