EAP peer: Simplify EAP method registration call

EAP peer: Simplify EAP method registration call

Free the allocated structure in error cases to remove need for each EAP
method to handle the error cases separately. Each registration function
can simply do "return eap_peer_method_register(eap);" in the end of the
function.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>