[ofw] [VNIC] Added suppot for ipv6 checksum offload

[Sean Hefty]

>Added support for ipv6 checksum offload.
>- fixed potential netpath null dereference
>- fixed control path initialization potential flaw,
>- simplified LBFO a bit and removed NdisMRemoveMiniport since
>  it breaks adapter reset-reinitialization.
>- removed cmd reset request (doesn't make sense when path is broken).
>- hung flag set change
>- debug messages, replace some macros with inline funcs, some code
>cleanup and formatting.
>INF changes
> - fixed service name.
> - mtu payload size can be modified in 100 bytes increments( was 500).

A couple other requests:

Can you please submit these as separate patches to make it easier to review?
Can you include the function names in the diff?
And the patch had line wrap issues and was reversed (the 'inserts' should have
been the 'deletes').

- Sean