Inject auth token into tags

The reference keymaster at system/keymaster still expects to receive its
auth tokens in the tags, rather than as a separate parameter. This
change injects the separate parameter passed to the KM4 HAL as a legacy
tag in the request.

Longer term, system/keymaster should support a separate authToken
parameter, and it should be serialized and sent to Trusty separately.

Test: Keymaster VTS + Keystore CTS (sans attestation)
Change-Id: Ie69cbd358504bb7612f7d55158509043cdad4e4e