[gsm0408] Make the generate_lai usable by other code

Prefix generate_lai with gsm0408 and update call sites. It will
be used from within bsc_hack.c
diff --git a/src/gsm_04_08.c b/src/gsm_04_08.c
index 3902d94..4293891 100644
--- a/src/gsm_04_08.c
+++ b/src/gsm_04_08.c
@@ -75,7 +75,7 @@
 	val = val / 10;
 }
 
-static void generate_lai(struct gsm48_loc_area_id *lai48, u_int16_t mcc, 
+void gsm0408_generate_lai(struct gsm48_loc_area_id *lai48, u_int16_t mcc, 
 			 u_int16_t mnc, u_int16_t lac)
 {
 	u_int8_t bcd[3];
@@ -162,7 +162,7 @@
 	gh->msg_type = GSM48_MT_MM_LOC_UPD_ACCEPT;
 
 	lai = (struct gsm48_loc_area_id *) msgb_put(msg, sizeof(*lai));
-	generate_lai(lai, bts->network->country_code,
+	gsm0408_generate_lai(lai, bts->network->country_code,
 		     bts->network->network_code, bts->location_area_code);
 
 	mid = msgb_put(msg, MID_TMSI_LEN);