drm/i915/psr: Restore PSR interrupt handler for HSW

Add the PSR interrupt handling code back for HSW. Looks like
the removal was never completed anyway since the irq setup
code was lest untouched.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230609141404.12729-8-ville.syrjala@linux.intel.comReviewed-by: Jouni Högander <jouni.hogander@intel.com>

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

@@ -749,6 +749,20 @@ void ivb_display_irq_handler(struct drm_i915_private *dev_priv, u32 de_iir)
 	if (de_iir & DE_ERR_INT_IVB)
 		ivb_err_int_handler(dev_priv);
 
+	if (de_iir & DE_EDP_PSR_INT_HSW) {
+		struct intel_encoder *encoder;
+
+		for_each_intel_encoder_with_psr(&dev_priv->drm, encoder) {
+			struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
+			u32 psr_iir;
+
+			psr_iir = intel_uncore_rmw(&dev_priv->uncore,
+						   EDP_PSR_IIR, 0, 0);
+			intel_psr_irq_handler(intel_dp, psr_iir);
+			break;
+		}
+	}
+
 	if (de_iir & DE_AUX_CHANNEL_A_IVB)
 		intel_dp_aux_irq_handler(dev_priv);