MFC r227461:

MFC r227461:
Style change.
- Make it easier to port the USB code to other platforms by only using
one set of memory functions for clearing and copying memory. None of
the memory copies are overlapping. This means using bcopy() is not
required.
- Fix a compile warning when USB_HAVE_BUSDMA=0
- Add missing semicolon in avr32dci.
- Update some comments.

git-svn-id: svn://svn.freebsd.org/base/stable/8@228229 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f