repack_bootimg: Update --ramdisk_add usages am: b166bd7879 am: e8dd60790c am: 1f9c6ff74b

Original change: https://android-review.googlesource.com/c/platform/system/tools/mkbootimg/+/1864426

Change-Id: I6cc7170cc48f065c1ce9e7b7c9e5047ebafc2362