This change allows users to specify TPM1.2 support rather than remove it. go-attestation will build without needing Trousers/TSPI support. The flip-side of this is that TPM1.2 does not just work; TPM1.2 users need to include the `tspi` build tag.
Goal is to switch current builder run internally by Google over to GitHub Actions.
PiperOrigin-RevId: 380881515