libdmabufheap: Fix permissions when opening ION device am: 2bc3e2c39d am: c6f8b1642a am: 33441afe66

Original change: https://android-review.googlesource.com/c/platform/system/memory/libdmabufheap/+/1362348

Change-Id: I19a9de78c0527c7a5dc7d1829474ffef7b977faa
tree: f0993c49ed90d53edfb1a6e29cacb718ae6c9378
  1. include/
  2. tests/
  3. Android.bp
  4. BufferAllocator.cpp
  5. BufferAllocatorWrapper.cpp