Require OsmoMgw in OsmoBsc and update tests

Since Change-Id Ia2882b7ca31a3219c676986e85045fa08a425d7a, osmo-bsc
uses osmo-mgw and utilizes libosmo-mgcp-client to talk to it.

This commit fixes latest constant failures in voice suite.

Change-Id: I1dadd781a357fce33e7bde55e4bcbdaeb4633359
diff --git a/src/osmo_gsm_tester/templates/osmo-bsc.cfg.tmpl b/src/osmo_gsm_tester/templates/osmo-bsc.cfg.tmpl
index d79bb2b..2f06710 100644
--- a/src/osmo_gsm_tester/templates/osmo-bsc.cfg.tmpl
+++ b/src/osmo_gsm_tester/templates/osmo-bsc.cfg.tmpl
@@ -74,7 +74,10 @@
  token msc_token_23_42
  core-mobile-country-code ${bsc.net.mcc}
  core-mobile-network-code ${bsc.net.mnc}
- ip.access rtp-base 8000
+ ip.access rtp-base 25000
+ mgw remote-ip ${mgw.ip_address.addr}
+ mgw remote-port 2427
+ mgw endpoint-range 1 31
  timeout-ping 1800
  timeout-ping advanced
  timeout-pong 60