heimdalcred: no krb5 time types in khm structs
heimdalcred: no krb5 time types in khm structs

Use khm_int64 for time values in khm structs so the structure
has the same size regardless of use 32-bit time setting.

Change-Id: I808c097a2dd34c13dd80c17edb7f7f21397fd905

secure-endpoints/netidmgr,secure-endpoints/netidmgr,secure-endpoints/netidmgr,secure-endpoints/netidmgr,secure-endpoints/netidmgr