gsmtap.h: Define a packet type for encapsulation of GSM RLP frames

This allows us to feed RLP frames (occurring in GSM CSD) into wireshark
for dissection.

Change-Id: Ibb7f0731c31e5a5cd2911f733da5510ce0f3a1d6
diff --git a/include/osmocom/core/gsmtap.h b/include/osmocom/core/gsmtap.h
index b0985f0..2387b20 100644
--- a/include/osmocom/core/gsmtap.h
+++ b/include/osmocom/core/gsmtap.h
@@ -49,6 +49,7 @@
 #define GSMTAP_TYPE_QC_DIAG		0x11	/* Qualcomm DIAG frame */
 #define GSMTAP_TYPE_LTE_NAS		0x12	/* LTE Non-Access Stratum */
 #define GSMTAP_TYPE_E1T1		0x13	/* E1/T1 Lines */
+#define GSMTAP_TYPE_GSM_RLP		0x14	/* GSM RLP frames as per 3GPP TS 24.022 */
 
 /* ====== DO NOT MAKE UNAPPROVED MODIFICATIONS HERE ===== */