When Android userdata partition has been erased in fastbootd, call
oem specific API doOemSpecificErase() to wipe other userdata in
device.
If oem doesn't implement this specific API in fastboot_hal lib,
fastbootd will receive 'NOT_SUPPORTED' return status.
Bug: 169173873
Change-Id: I9b6a5a4aaed31d1168e633418b189f9bb6d34d01