dtimage.mk: fix the path of vendor-package-ver.mk am: 26df8471f6 am: 9c8dcdec92 am: 2d0f44dcfc am: db5e05cdcc

Original change: https://android-review.googlesource.com/c/device/linaro/hikey/+/2000571

Change-Id: Idebb9d6bbb3c0befd74048bcaa09b4805ceded92