crypto: return the retval of HMAC_Update

Fixes coverity scan issue 55489.

PR-URL: https://github.com/nodejs/node/pull/10891


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>