Move DTX settings to BTS

* Add per-BTS DTX settings
* Configure Uplink and Downlink DTX separately
* Deprecate global DTX option (it was never tested/used anyway)
* Use libosmocore function for DTX indicator in System
  Information (previously it was incorrectly assigned for half-rate
  channels)

Related: OS#22
Change-Id: I3d55168475ad47044b6238b55846ea22bdd518a4
Reviewed-on: https://gerrit.osmocom.org/40
Tested-by: Jenkins Builder
Reviewed-by: Holger Freyther <holger@freyther.de>
diff --git a/openbsc/doc/examples/osmo-bsc/osmo-bsc.cfg b/openbsc/doc/examples/osmo-bsc/osmo-bsc.cfg
index a17127d..56e4724 100644
--- a/openbsc/doc/examples/osmo-bsc/osmo-bsc.cfg
+++ b/openbsc/doc/examples/osmo-bsc/osmo-bsc.cfg
@@ -40,7 +40,6 @@
  timer t3119 0
  timer t3122 0
  timer t3141 0
- dtx-used 0
  subscriber-keep-in-ram 0
  bts 0
   type nanobts
@@ -55,6 +54,8 @@
   channel allocator ascending
   rach tx integer 9
   rach max transmission 7
+  dtx uplink force
+  dtx downlink
   ip.access unit_id 0 0
   oml ip.access stream_id 255 line 0
   neighbor-list mode manual-si5