bts_features.h: Introduce BTS_FEAT_PAGING_COORDINATION

This feature indicates if the given BTS supports paging coordination,
that is the transmission of CS paging (received on Abis) to be sent
via PACCH/PCU in PS domain fro MS with active TBF.

Change-Id: Ifb2e83eaf05dd36e5b203ed2de1a74864b039e38
Related: OS#2406
diff --git a/include/osmocom/gsm/bts_features.h b/include/osmocom/gsm/bts_features.h
index 27a3983..22461a6 100644
--- a/include/osmocom/gsm/bts_features.h
+++ b/include/osmocom/gsm/bts_features.h
@@ -24,6 +24,7 @@
 	BTS_FEAT_SPEECH_F_AMR,
 	BTS_FEAT_SPEECH_H_AMR,
 	BTS_FEAT_ETWS_PN,
+	BTS_FEAT_PAGING_COORDINATION,	/* BTS hands CS paging to PCU/PACCH */
 	_NUM_BTS_FEAT
 };