hyperv/hn: Use vmbus xact for RNDIS query.

And switch MAC address query to use new RNDIS query function.

Sponsored by:   Microsoft
Differential Revision:  https://reviews.freebsd.org/D7639

hyperv/hn: Save the adopted NDIS version for RNDIS to use later.

Sponsored by:   Microsoft
Differential Revision:  https://reviews.freebsd.org/D7640

hyperv/hn: Use vmbus xact for RNDIS set.

And use new RNDIS set to configure NDIS offloading parameters.

Sponsored by:   Microsoft
Differential Revision:  https://reviews.freebsd.org/D7641

hyperv/hn: Add definition for NDIS media state.

Sponsored by:   Microsoft
Differential Revision:  https://reviews.freebsd.org/D7652