Things to do for the bktr driver, in no special order:

o check for a possibility to replace remaining vtophys()
o clean up bt8xx.h
o does it work on alpha?
o use NetBSD's own i2c-functions
o look for cause of warning:
  bktr0: ioctl: tsleep error 35 200001c
  See mail by Stuart Sharpe <stu@drazi.demon.co.uk>
  on Wed, 4 Oct 2000 21:50:11 +0100 (BST) on current-users,
  Message-Id: <200010042050.e94KoEg00353@drazi.demon.co.uk>
o split up contents of bktr directory to better places? (also fix
  bktr2netbsd in that case)
o replace unsigned long by u_int32_t (and similar for int/short?)