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>
diff --git a/drivers/gpu/drm/radeon/r600_hdmi.c b/drivers/gpu/drm/radeon/r600_hdmi.c
index e419b98..95397b2 100644
--- a/drivers/gpu/drm/radeon/r600_hdmi.c
+++ b/drivers/gpu/drm/radeon/r600_hdmi.c
@@ -461,7 +461,9 @@
 
 	if (rdev->irq.installed) {
 		/* if irq is available use it */
-		radeon_irq_kms_enable_afmt(rdev, dig->afmt->id);
+		/* 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);
 	}
 
 	dig->afmt->enabled = true;