change some identifiers from u_int64_t to unsigned long long

makes printf much easier on 64bit platforms...
diff --git a/openbsc/src/db.c b/openbsc/src/db.c
index b86348c..369505a 100644
--- a/openbsc/src/db.c
+++ b/openbsc/src/db.c
@@ -592,7 +592,7 @@
 }
 
 int db_subscriber_assoc_imei(struct gsm_subscriber* subscriber, char imei[GSM_IMEI_LENGTH]) {
-	u_int64_t equipment_id, watch_id;
+	unsigned long long equipment_id, watch_id;
 	dbi_result result;
 
 	strncpy(subscriber->equipment.imei, imei,