Using mbedtls commit f9c599cd8ac9d00c484d4f5b027e18c6af4f9fdf before
they re-licensed to Apache 2.0, so we have a GPL-v2-or-later bsae64
implementation and avoid having code under a different license in the
tree.
This code is the unmodified import, so we can record any local changes
compared to the original version.
Change-Id: I39a9d3ab98257d21b9439b00528c744efa372c14