drm/radeon: disable audio format interrupts on Evergreen

The audio format change interrupts are an aid in debugging,
but not required for operation.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/r600_hdmi.c

@@ -461,6 +461,8 @@ void r600_hdmi_enable(struct drm_encoder *encoder)
 
 	if (rdev->irq.installed) {
 		/* if irq is available use it */
+		/* XXX: shouldn't need this on any asics.  Double check DCE2/3 */
+		if (!ASIC_IS_DCE4(rdev))
 			radeon_irq_kms_enable_afmt(rdev, dig->afmt->id);
 	}