[RFC/T] fan control unit driver for PowerMac 7.2

[Andreas Tobler]

Hi Peter, others

Over the past few moons I've written a fcu driver (with Nathans help) 
which should allow to control the fans in the older PowerMac7.2.

I'll post it here to get some feedback from you and others.

To make it work you need to place it in sys/powerpc/powermac
In the sys/conf/files.powerpc(64) you need to add this:

powerpc/powermac/fcu.c		optional	powermac

I developed the driver on the powermac64 branch. But I expect it to work 
also on 32-bit. But...

I have one issue which is not solved yet. To make it read the i2c 
devices I had to increase the DELAY in kiic_writereg to 100. This might 
be specific to my G5, a dual 1.8GHz machine.

Currently it is one big file with several sub components.

I'd welcome some feedback.

TIA,
Andreas