PATCH: iicbus(4) locking, please test

I have a first attempt at adding locking to iicbus(4).  Originally my goal was 
to do this so if_ic(4) could be locked.  However, if_ic(4) does evil things 
in its ioctl routine so I'm actually going to leave that alone unless someone 
says they want to test possible changes.  Back to iicbus(4), this patch adds 
locking to the core of iicbus and the various related drivers.  A few drivers 
(ixp_iic, lpbb, and bktr) just use Giant for their driver lock for now.  It 
has been compiled on my laptop (i386) but not anything else yet.

http://www.FreeBSD.org/~jhb/patches/iicbus.patch

-- 
John Baldwin