compositor-drm: Use matrix type to test for drm plane compatibility

The drm planes (sprites) only support translation and scaling.  Now that
we have matrix.type, we can just look there to see if the transform is
compatible with kms.

src/compositor-drm.c

@@ -698,32 +698,8 @@ drm_output_check_sprite_format(struct drm_sprite *s,
 static int
 drm_surface_transform_supported(struct weston_surface *es)
 {
-	struct weston_matrix *matrix = &es->transform.matrix;
-	int i;
-
-	if (!es->transform.enabled)
-		return 1;
-
-	for (i = 0; i < 16; i++) {
-		switch (i) {
-		case 10:
-		case 15:
-			if (matrix->d[i] != 1.0)
-				return 0;
-			break;
-		case 0:
-		case 5:
-		case 12:
-		case 13:
-			break;
-		default:
-			if (matrix->d[i] != 0.0)
-				return 0;
-			break;
-		}
-	}
-
-	return 1;
+	return !es->transform.enabled ||
+		(es->transform.matrix.type < WESTON_MATRIX_TRANSFORM_ROTATE);
 }
 
 static struct weston_plane *