Resolve OP-TEE build issues on aarch64 hosts.

[msgilligan]

I was able to successfully build OP-TEE in the 3.22.0 or 4.0.0 era on aarch64 systems, but when I tried with 4.2.0 and later, I ran into a handful of build issues.

I initially created OP-TEE/build#747 to report the problem.

What appears to be the last remaining issue is related to Rust linking (it works on x86_64 and fails on aarch64) This issue on the Rust subproject is tracking progress: apache/incubator-teaclave-trustzone-sdk#135)

At this point I have a workaround using Docker that allows me to make progress on the ValidiTEE TA itself.