The EAP-method's .probe methods only checked the method name so do that
in eap.c instead and allocate method state in .load_settings. Rename
method's .remove method to .free to improve the naming.
This EAP method uses nearly all the logic from EAP-AKA. The major
difference is it uses the new key derivation functions for AKA' as
well as the SHA256 MAC calculation.
EAP-AKA' uses SHA256 rather than SHA1 to generate the packet MAC's.
This updates the derive MAC API to take the EAP method type and
correctly use the right SHA variant to derive the MAC.
