MFC r219048, r219004, r218475 and r204632.

MFC r219048, r219004, r218475 and r204632.
- The NetBSD Foundation has granted permission to remove clause 3 and 4 from
  their software.
- use device_printf() instead of printf() to give more accurate warnings.
- use memcpy() instead of bcopy().
- add missing #if's for non-FreeBSD compilation.
- Add missing xhci(4) manual page.
- Minor update in some USB manual pages.
- Correct USB 3.0 wire-speed to 5.0Gbps

Approved by:	thompsa (mentor)

git-svn-id: svn://svn.freebsd.org/base/stable/8@220308 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f