cosmetic: update comments that refer to weston_surface_update_transform()

weston_surface_update_transform() no longer exists, except in comments.

Fix that.

[Pekka Paalanen: don't lose the full comment in compositor-drm.c.]

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
diff --git a/src/compositor-drm.c b/src/compositor-drm.c
index 9c83b1a..e4496e7 100644
--- a/src/compositor-drm.c
+++ b/src/compositor-drm.c
@@ -900,7 +900,7 @@
 
 	/*
 	 * Calculate the source & dest rects properly based on actual
-	 * position (note the caller has called weston_surface_update_transform()
+	 * position (note the caller has called weston_view_update_transform()
 	 * for us already).
 	 */
 	pixman_region32_init(&dest_rect);