ofw syscons brightness patch

[Peter Grehan]

Hi Justin,

> Attached is a patch that adds brightness control to ofw syscons
> (dev.sc.0.brightness sysctl). Pretty simple. Comments and tests
> requested. Hopefully the listserv doesn't eat the patch.

  Is it possible to have the value in the sysctl be 0-100, or 0-10 ? It 
might be a bit confusing for the user to have to know that the range is 
0x34-0xff, and have the sysctl code clamp to these.

  Are the MIN_BRIGHTNESS/MAX_BRIGHTNESS values the same for all models ?

later,

Peter.