Delete buile-mbedtls-amis.yaml

The new AMI build job has been migrated to production
https://git.trustedfirmware.org/ci/tf-ci-scripts.git/tree/build-aws-amis.yaml

Signed-off-by: Arthur She <arthur.she@linaro.org>
Change-Id: I95a316b0193cbaa38f1a40987357f6a399271f53
1 file changed