Bring USB fixes for linux(4).

Bring USB fixes for linux(4).

Intention of this commit is to let us take a full advantage
of libusb(8) ported to Linux. This decreases a possibility of getting
any collisions within ioctl() "command" space, especially with
relation to  LINUX_SNDCTL_SEQ... stuff.

Basically, we provide commands, that will be mapped in the kernel
to correct ones and forward those to the USB layer. Port enabling
functionality brought with this patch is here:

	http://www.freebsd.org/cgi/query-pr.cgi?pr=146895

Bump __FreeBSD_version to catch, since which version installing a
port makes sense.

This patch should bring no regressions. So far, only i386 is tested.

Tested by:	thompsa@
Reviewed by:	thompsa@
OKed by:	netchild@