Merge first bktr-sf import.

Import of current state of bktr(4) in sourceforge repository.
Changes since last import:
. lots of whitespace cleanups
. typo fixes (e.g. hz, compatibilty)
. fix brightness ioctl return value
. wait

Import of current state of bktr(4) in sourceforge repository.
Changes since last import:
. lots of whitespace cleanups
. typo fixes (e.g. hz, compatibilty)
. fix brightness ioctl return value
. wait for int ready using DELAY() instead of tight loop

show more ...

Import release 2.17 of the bktr driver.
Changes: Integration of some NetBSD changes. (FreeBSD version now is also
usable as a KLD (~= LKM).)