Allow hostapd/config.h and wpa_supplicant/config_ssid.h coexist

Move the shared IEEE 802.11w enum definition into src/common/defs.h to
avoid redefinition when both configuration structures are included into
the same file.

src/common/defs.h

@@ -206,4 +206,11 @@ typedef enum {
 #define MLME_SETPROTECTION_KEY_TYPE_GROUP 0
 #define MLME_SETPROTECTION_KEY_TYPE_PAIRWISE 1
 
+
+enum mfp_options {
+	NO_IEEE80211W = 0,
+	IEEE80211W_OPTIONAL = 1,
+	IEEE80211W_REQUIRED = 2
+};
+
 #endif /* DEFS_H */