Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Build fixups for the new USB stack.

Remove dependency on dev/usb/usbdevs.h, in preparation for its
disappearing from the tree. We already were splitting the baby (using
the symbol for the vendor BROADCOM, but not for the device). Use
#defines for both.

Broadcom firmware loading module.. The actual firmware files will follow when
the legal status has been confirmed, in the meanwhile they can be
downloaded from the location in the README file.