Rename getIonMappedSizeKb to getDmabufMappedSizeKb am: 6ae0be89b9

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1576749

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I892f92e8fa37d0f71f679c633b59b5c9523547ff