PMU backlight panel fix

[David Zeuthen]

On Sun, 2007-02-04 at 23:32 +0000, Richard Hughes wrote:
> New kernels export the PMU backlight as a kernel backlight class, and
> GET_BACKLIGHT and SET_BACKLIGHT ioctls fail. This means that HAL fails
> to set the brightness on PPC hardware.
> 
> We should check for the existence of the backlight device (like in
> acpi.c) before we add the PMU backlight to avoid having two backlight
> devices, one of which that does not work.
> 
> The patch also gives the generic backlight class a name, so it does not
> show up as unknown device.
> 
> Okay to commit?

Go for it. Thanks. Are there other places where we need things like
this?

     David