gprs_bssgp: add IE parser/generator for RIM Routing Information

The RIM Routing Information IE (see also 3GPP TS 48.018, section
11.3.70) is used to control the flow of BSSGP rim messages at the SGSN.

Change-Id: I6f88a9aeeb50a612d32e9efd23040c9740bc4f11
Related: SYS#5103
diff --git a/include/osmocom/gprs/protocol/gsm_24_301.h b/include/osmocom/gprs/protocol/gsm_24_301.h
new file mode 100644
index 0000000..d4bcd87
--- /dev/null
+++ b/include/osmocom/gprs/protocol/gsm_24_301.h
@@ -0,0 +1,11 @@
+/*! \file gsm_24_301.h */
+
+#pragma once
+
+/*! Tracking area TS 24.301, section 9.9.3.32 */
+struct osmo_eutran_tai {
+	uint16_t mcc;
+	uint16_t mnc;
+	bool mnc_3_digits;
+	uint16_t tac;
+};