Use a consistent type for the number of HMAC algorithms.
This fixes a bug which resulted in a warning on the userland
stack, when compiled on Windows.
Thanks to Peter Kasting from Google for reporting the issue and
provinding a potential fix.

MFC after: 3 days


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271673 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f