Decode more fields when dumping USB descriptors.
- Some minor style changes while at it.

Submitted by:	Dmitry Luhtionov <dmitryluhtionov@gmail.com>
MFC after:	1 week


git-svn-id: svn+ssh://svn.freebsd.org/base/head@274435 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f