ANDROID: fips140: support "evaluation testing" builds via build.sh

Allow the following command to be run to make a build of fips140.ko
that has CONFIG_CRYPTO_FIPS140_MOD_EVAL_TESTING enabled:

    BUILD_CONFIG=common/build.config.gki.aarch64.fips140_eval_testing ./build/build.sh

Bug: 188620248
Change-Id: I0e0be487974c6ad40f3135fc5fec6aa107aab78c
Signed-off-by: Eric Biggers <ebiggers@google.com>