Add arm64 as a valid architecture.

BUG=None
TEST=Tested in my directory (with build_tc.py --board=arm64-generic)

Change-Id: Ib4d0e61a77c279c2c47c5d8e6ac6b71af4adb25e
Reviewed-on: https://chrome-internal-review.googlesource.com/232166
Commit-Ready: Caroline Tice <cmtice@google.com>
Tested-by: Caroline Tice <cmtice@google.com>
Reviewed-by: Han Shen <shenhan@google.com>
1 file changed