[PATCH][OF] Add of_device_is_available function

[Benjamin Herrenschmidt]

On Tue, 2008-02-26 at 14:44 -0800, David Miller wrote:
> From: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> Date: Wed, 27 Feb 2008 08:45:37 +1100
> 
> > I doubt we do that. Properties that contain things like ranges, or "reg"
> > properties are expected to be of a size that is a multiple of
> > #size-cells/#address-cells and I'm not sure that won't break things here
> > or there if they suddenly get one more byte..
> > 
> > Or do you mean you/we are appending that-without- changing the length
> > field ?
> 
> Right, simply don't change the length field.  Put the zero byte
> at offset "length + 1"
> 
> It's stupid to validate NULL termination everywhere when we
> can make it an invariant in one spot.

Fair enough.

Ben.