drm/i915: Pass old crtc state to skylake_scaler_disable()

To make life easier in the future let's pass the old crtc state
to skylake_scaler_disable() just like we already do for
for its ancestor ironlake_pfit_disable().

Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191213195217.15168-3-ville.syrjala@linux.intel.comReviewed-by: José Roberto de Souza <jose.souza@intel.com>

drivers/gpu/drm/i915/display/intel_display.c

@@ -5767,8 +5767,9 @@ static int skl_update_scaler_plane(struct intel_crtc_state *crtc_state,
 	return 0;
 }
 
-static void skylake_scaler_disable(struct intel_crtc *crtc)
+static void skylake_scaler_disable(const struct intel_crtc_state *old_crtc_state)
 {
+	struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->uapi.crtc);
 	int i;
 
 	for (i = 0; i < crtc->num_scalers; i++)
@@ -6760,7 +6761,7 @@ static void haswell_crtc_disable(struct intel_atomic_state *state,
 	intel_dsc_disable(old_crtc_state);
 
 	if (INTEL_GEN(dev_priv) >= 9)
-		skylake_scaler_disable(crtc);
+		skylake_scaler_disable(old_crtc_state);
 	else
 		ironlake_pfit_disable(old_crtc_state);