Interworking: Use unsigned integer for bitfield

Signed integer with one-bit value does not make much sense, so clean
this up by using an unsigned integer instead.

wpa_supplicant/wpa_supplicant_i.h

@@ -591,9 +591,9 @@ struct wpa_supplicant {
 	struct gas_query *gas;
 
 #ifdef CONFIG_INTERWORKING
-	int fetch_anqp_in_progress:1;
-	int network_select:1;
-	int auto_select:1;
+	unsigned int fetch_anqp_in_progress:1;
+	unsigned int network_select:1;
+	unsigned int auto_select:1;
 #endif /* CONFIG_INTERWORKING */
 };