Allow PMKSA caching to be disabled on Authenticator

A new hostapd configuration parameter, disable_pmksa_caching=1, can now
be used to disable PMKSA caching on the Authenticator. This forces the
stations to complete EAP authentication on every association when WPA2
is being used.

src/ap/ap_config.h

@@ -288,6 +288,7 @@ struct hostapd_bss_config {
 	 */
 	u16 max_listen_interval;
 
+	int disable_pmksa_caching;
 	int okc; /* Opportunistic Key Caching */
 
 	int wps_state;