Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Add support for new USB to ethernet controller:
Moschip MCS7730/MCS7830

Submitted by: Rick van der Zwet <info@rickvanderzwet.nl>
Approved by: thompsa (mentor)