Add functions to read and write AVB_ATX permanent attributes
Trusty's AVB service can store permanent attributes in RPMB, and will
only allow the values to be written once. This patch enables reading and
writing permanent attributes by calling into Trusty. If RPMB is used to
store permanent attributes, they MUST be verified against write-once
hardware.
avb_do_tipc is refactored and documented.
Bug: 33051168
Test: manual test on imx6ul
Change-Id: If52762dc710e1e0265d7de508c6c1daaf62b7f0d
3 files changed
