mkdtboimg: Sanitize dt filename am: 4b929c464b am: 530ae759fc am: e1e0fa3320 am: 31fb2266b4 am: 70545b5d42

Original change: https://android-review.googlesource.com/c/platform/system/libufdt/+/1410171

Change-Id: I423d21068c996a88b9d3a8ad7600d6ffafb3be3e