There is no need to use eap_sim_db_identity_known() here since a new
AKA/Identity message is built only if the identity in the previous
response was not recognized. The first round is always used to request
AT_ANY_ID_REQ to meet the RFC 4187 recommendation on EAP method specific
identity request.
Signed-hostap: Jouni Malinen <j@w1.fi>