spitz backlight: fix brightness limiting

[Eric Miao]

On Thu, Oct 22, 2009 at 3:05 PM, Pavel Machek <pavel at ucw.cz> wrote:
> On Thu 2009-10-22 04:20:34, Eric Miao wrote:
>> It's a little bit weird it's called 'limit_mask' when I first converted it
>> to a spi driver. There must be some reasons, Richard, you've got
>> any ideas?
>
> Yes, the code was "interesting"...
>
> I can certainly do the rename, but maybe we can fix the issue now and
> do futher cleanups later?

Fair enough, I'm fine with that - I'd like this to go through Richard's
backlight tree if possible, though.