gss:krb5 only include enctype numbers in gm_upcall_enctypes

Make the value in gm_upcall_enctypes just the enctype values.
This allows the values to be used more easily elsewhere.

Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>