mgmt/osdp: cp: disallow unexpected SC responses

When CP has a secure channel active, it should never receive a
REPLY_CCRYPT or REPLY_RMAC_I. Since these responses change the SC state,
let's also make sure that they are accepted only when they are
expected: in response to commands CMD_CHLNG and CMD_SCRYPT respectively.

Reported-by: Eran Jacob <eran.jacob@otorio.com>
Signed-off-by: Siddharth Chandrasekaran <sidcha.dev@gmail.com>