implement support for 3-digit MNC with leading zeros

Add 3-digit flags and use the new RAI and LAI API from libosmocore throughout
the code base to be able to handle an MNC < 100 that has three digits (leading
zeros).

Note that in gbproxy_test.ok, 0-0 changes to 000-000 instead of 000-00, because
the parsed ra buffer is 000000 which results in 000-000, while 00f000 would
result in 000-00. IOW this is expected.

Change-Id: I7437dfaa586689e2bef0d4be6537e5577a8f6c26
diff --git a/src/gprs/gprs_utils.c b/src/gprs/gprs_utils.c
index 307699b..d7cef1c 100644
--- a/src/gprs/gprs_utils.c
+++ b/src/gprs/gprs_utils.c
@@ -239,8 +239,10 @@
 }
 
 int gprs_ra_id_equals(const struct gprs_ra_id *id1,
-			const struct gprs_ra_id *id2)
+		      const struct gprs_ra_id *id2)
 {
-	return (id1->mcc == id2->mcc && id1->mnc == id2->mnc &&
-		id1->lac == id2->lac && id1->rac == id2->rac);
+	return (id1->mcc == id2->mcc
+		&& !osmo_mnc_cmp(id1->mnc, id1->mnc_3_digits,
+				 id2->mnc, id2->mnc_3_digits)
+		&& id1->lac == id2->lac && id1->rac == id2->rac);
 }