handshake: add flag for FILS support

The handshake_state only holds a single AKM value. FILS depends on the AP
supporting EAP as well as FILS. The first time IWD connects, it will do a
full EAP auth. Subsequent connections (assuming FILS is supported) will use
FILS. But if the AP does not support FILS there is no reason to cache the
ERP keys.

This adds the supp_fils to the handshake_state. Now, station.c can set this
flag while building the handshake. This flag can later be checked when
caching the ERP keys.

src/handshake.h

@@ -108,6 +108,7 @@ struct handshake_state {
 	bool authenticator : 1;
 	bool wait_for_gtk : 1;
 	bool no_rekey : 1;
+	bool support_fils : 1;
 	uint8_t ssid[32];
 	size_t ssid_len;
 	char *passphrase;