[Intel-gfx] [PATCH 1/2] drm/i915: Use pipe_config state to disable ilk+ pfit

[Mika Kuoppala]

Daniel Vetter <daniel.vetter at ffwll.ch> writes:

> No more need to guard the write with a power well check on Haswell now
> that we have proper pfit state readout: We can simply only clear the
> pfit if it's actually on.
>
> This removes some duplication of knowledge between the haswell pfit
> disable and pfit state readout code about.
>
> While at it extract a little helper for this.
>
> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>

Reviewed-by: Mika Kuoppala <mika.kuoppala at intel.com>