add BTS_FEAT_VAMOS

Change-Id: Ic3bd1b8075f76d1f35499faa68fad70698ee9a00
diff --git a/include/osmocom/gsm/bts_features.h b/include/osmocom/gsm/bts_features.h
index d0dbe48..ac2c760 100644
--- a/include/osmocom/gsm/bts_features.h
+++ b/include/osmocom/gsm/bts_features.h
@@ -28,6 +28,7 @@
 	BTS_FEAT_IPV6_NSVC,
 	BTS_FEAT_ACCH_REP,
 	BTS_FEAT_CCN, /* Is CCN supported by the cell? TS 44.060 sec 8.8.2 */
+	BTS_FEAT_VAMOS, /* Is the BTS VAMOS capable? */
 	_NUM_BTS_FEAT
 };