drm/i915: Pass plane and crtc to intel_update_sprite_watermarks

We're going to want to know the crtc in the watermark code to avoid
doing more work than we have to. We should also pass the plane we're
disabling so that we know where to stick our watermark parameters
without having to go look the plane up.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>