Add VGCS UPLINK GRANT message structure to gsm_04_08.h

Change-Id: I8a16ce4ddc7a36e0db2936227a910b4d53cddfca
diff --git a/include/osmocom/gsm/protocol/gsm_04_08.h b/include/osmocom/gsm/protocol/gsm_04_08.h
index a4e05d6..c70e2e6 100644
--- a/include/osmocom/gsm/protocol/gsm_04_08.h
+++ b/include/osmocom/gsm/protocol/gsm_04_08.h
@@ -1202,6 +1202,13 @@
 #endif
 } __attribute__ ((packed));
 
+/* TS 44.018 Section 9.1.49 */
+struct gsm0408_vgcs_ul_grant {
+	struct gsm48_hdr hdr;
+	struct gsm48_req_ref req_ref;
+	uint8_t ta;
+} __attribute__ ((packed));
+
 /* Section 9.1.43a System Information type 13 */
 struct gsm48_system_information_type_13 {
 	struct gsm48_system_information_type_header header;