Ok, after writing up something in the way of a perl script to make some
sense of the data for voltages, and finding that there is no sense to
make, I took a longer look at things.

The it87 driver in 2.5.x is doing some, down right /odd/ math on the
numbers for the in_input* readings, and the 2.4.x driver is doing
something quite different.

And while it might be possible to get sane numbers out of the 2.5.x
driver, people /expect/ to get the numbers that they were getting from
2.4.x.

So this patch puts things back to the simpler calculations done by the
2.4.x lm-sensors drivers, and my script confirms that the numbers come
out right.