libdmabufheap: Do not create heap mappings without ION support am: 0f2cc9e07e am: d2e5cc71c9

Original change: https://android-review.googlesource.com/c/platform/system/memory/libdmabufheap/+/1792810

Change-Id: I9125a44af80a413ec8e2f83c58f6e72b107a21b6
tree: f71e233c230fb661f6af0aa5c05e6760a7f243fb
  1. include/
  2. tests/
  3. Android.bp
  4. BufferAllocator.cpp
  5. BufferAllocatorWrapper.cpp