EAP: Increase the maximum number of message exchanges

EAP: Increase the maximum number of message exchanges

Allow 100 rounds of EAP messages if there is data being transmitted.
Keep the old 50 round limit for cases where only short EAP messages are
sent (i.e., the likely case of getting stuck in ACK loop).

This allows larger EAP data (e.g., large certificates) to be exchanged
without breaking the workaround for ACK loop interop issues.

Signed-off-by: Jouni Malinen <j@w1.fi>