FileMap::create: remove duplicate addition. am: 54794ac613 am: 2912d9c190 am: 98e213207f

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/core/+/12393457

Change-Id: I8aeee458349a540c6a75fce57fd4a1d8b5b75eb3