Install sample cfg file to /etc/osmocom

Change-Id: Ib871a3cd14386ef6e6b512a3d66e7e7a839295a5
diff --git a/debian/osmo-trx-uhd.install b/debian/osmo-trx-uhd.install
index b7ec5ca..77236ca 100644
--- a/debian/osmo-trx-uhd.install
+++ b/debian/osmo-trx-uhd.install
@@ -1,3 +1,4 @@
+etc/osmocom/osmo-trx-uhd.cfg
 lib/systemd/system/osmo-trx-uhd.service
 /usr/bin/osmo-trx-uhd
 /usr/share/doc/osmo-trx/examples/osmo-trx-uhd/osmo-trx-usrp_b200.cfg /usr/share/doc/osmo-trx/examples/osmo-trx-uhd/