Enable USBIP support.

This is just the kernel support for USBIP.

The usbip userspace package in the Ubuntu repository is obsolete so the latest version will need to be built manually by the user. See https://bugs.launchpad.net/ubuntu/+source/usbip/+bug/898003 for more details.
Merge pull request #52 from VittGam/patch-1

Enable USBIP support.