drm: radeon: add some debug output when getparam is called with unknown

Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/char/drm/radeon_state.c b/drivers/char/drm/radeon_state.c
index 39a7f68..99589fe 100644
--- a/drivers/char/drm/radeon_state.c
+++ b/drivers/char/drm/radeon_state.c
@@ -2997,6 +2997,7 @@
 			value = RADEON_CARD_PCI;
 		break;
 	default:
+		DRM_DEBUG("Invalid parameter %d\n", param.param);
 		return DRM_ERR(EINVAL);
 	}