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)

style(9) fixes.

Reported by: ru

- Add Intel firmwares for Intel PRO/Wireless LAN 2100/2200/2915 cards in a
uuencoded format along with their respective LICENSE files.
- Add new share/doc/legal directory to BSD.usr.dist mtree file. This is the
place we install LICENSE files for restricted firmwares.
- Teach firmware(9) and kmod.mk about licensed firmwares. Restricted firmwares
won't load properly unless legal.<name>.license_ack is set to 1, either
via kenv(1) or /boot/loader.conf.

Reviewed by: mlaier, sam
Permitted by: Intel (via Andrew Wilson)
MFC after: 1 month