Add new USB ID.

PR:		usb/182936
Submitted by:	Keith White <kwhite@site.uottawa.ca>
MFC after:	1 week
Remove two instances of ARGSUSED comment, and wrap lines nearby the
code that is to be changed.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Similar to debug.iosize_max_clamp sysctl, introduce
devfs_iosize_max_clamp sysctl, which allows/disables SSIZE_MAX-sized
i/o requests on the devfs files.

Sponsored by:	The FreeBSD Foundation
Reminded by:	Dmitry Sivachenko <trtrmitya@gmail.com>
MFC after:	1 week
By default, allow up to SSIZE_MAX i/o for non-devfs files.

Sponsored by:	The FreeBSD Foundation
Reminded by:	Dmitry Sivachenko <trtrmitya@gmail.com>
MFC after:	1 month
X-MFC-note:	stable/10 only
Add a sysctl kern.disallow_high_osrel which disables executing the
images compiled on the world with higher major version number than the
high version number of the booted kernel.  Default to disable.

Sponsored by:	The FreeBSD Foundation
Discussed with:	bapt
MFC after:	1 week