add RSL_IE_OSMO_TRAINING_SEQUENCE

This IE is explained in the Abis manual in osmo-bts commit
Ie583bd5969fdb45f772af198033e58d7c4077306
http://git.osmocom.org/osmo-bts/commit/?id=823cd529649b667af20bfa4e383255a8ed5931f1

Change-Id: I573c26b1431ee789e42f6fa620947b003c384dc0
diff --git a/src/gsm/rsl.c b/src/gsm/rsl.c
index 2ab49c2..8d34543 100644
--- a/src/gsm/rsl.c
+++ b/src/gsm/rsl.c
@@ -127,6 +127,7 @@
 		[RSL_IE_LLP_APDU]		= { TLV_TYPE_TLV },
 		[RSL_IE_SIEMENS_MRPCI]		= { TLV_TYPE_TV },
 		[RSL_IE_OSMO_REP_ACCH_CAP]	= { TLV_TYPE_TLV },
+		[RSL_IE_OSMO_TRAINING_SEQUENCE]	= { TLV_TYPE_TLV },
 		[RSL_IE_IPAC_PROXY_UDP]		= { TLV_TYPE_FIXED, 2 },
 		[RSL_IE_IPAC_BSCMPL_TOUT]	= { TLV_TYPE_TV },
 		[RSL_IE_IPAC_REMOTE_IP]		= { TLV_TYPE_FIXED, 4 },