msc: generate Milenage ck in f_get_expected_encryption()

Instead of overwriting the ck of the original auth vector, generate the
Milenage-on-GERAN Ck key only for the expected ciphering IEs, centrally
in f_get_expected_encryption().

Related: SYS#5324
Change-Id: Iec618ba7fddb2290fc0137d99a9b8d5e2b428b98
1 file changed