drm/nouveau: reorganise bios header, add dcb connector type enums

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
index e73ce24..36a9692 100644
--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -613,6 +613,9 @@
 
 		clock *= 3;
 		break;
+	default:
+		BUG_ON(1);
+		return MODE_BAD;
 	}
 
 	if (clock < min_clock)