EAP-TTLS: Remove FreeRADIUS workaround for EAP-TTLS/MSCHAPv2

EAP-TTLS: Remove FreeRADIUS workaround for EAP-TTLS/MSCHAPv2

FreeRADIUS releases before 1.1.4 did not send MS-CHAP2-Success in
EAP-TTLS/MSCHAPv2. A wpa_supplicant workaround for that was added in
2005 and it has been enabled by default to avoid interoperability
issues. This could be disabled with all other EAP workarounds
(eap_workaround=0). However, that will disable some workarounds that are
still needed with number of authentication servers.

Old FreeRADIUS versions should not be in use anymore, so it makes sense
to remove this EAP-TTLS/MSCHAPv2 workaround completely to get more
complete validation of server behavior. This allows MSCHAPv2 to verify
that the server knows the password instead of relying only on the TLS
certificate validation.

Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>