EAP-SIM peer: Allow external SIM processing to be used

EAP-SIM peer: Allow external SIM processing to be used

This allows the new external_sim=1 case to be used to perform GSM
authentication step in EAP-SIM peer process. Following control interface
event is used to request the operation:

CTRL-REQ-SIM-<network id>:GSM-AUTH:<RAND1>:<RAND2>[:<RAND3>] needed
for SSID <SSID>

For example:
<3>CTRL-REQ-SIM-0:GSM-AUTH:5e3496ce7d5863b3b09f97f565513bc3:
73f0f0bc5c47bcbed6f572d07ab74056:447b784f08de80bdc2b1e100fccbb534
needed for SSID test

Response from external processing is returned with
CTRL-RSP-SIM-<network id> GSM-AUTH:<Kc1>:<SRES1>:<Kc2>:<SRES2>
[:<Kc3>:<SRES3>]

For example:
wpa_cli sim 0 GSM-AUTH:d41c76e0079247aa:2709ebfb:43baa77cfc8bcd6c:
0fa98dc1:a8ad1f6e30e

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