srsue, amarisoft/srsENB: Support setting rx/tx_gain attributes

Change-Id: I4228ba8746a54db4c17443718c01069d431361b9
diff --git a/src/osmo_gsm_tester/templates/srsenb.conf.tmpl b/src/osmo_gsm_tester/templates/srsenb.conf.tmpl
index 95b10f0..b3efd22 100644
--- a/src/osmo_gsm_tester/templates/srsenb.conf.tmpl
+++ b/src/osmo_gsm_tester/templates/srsenb.conf.tmpl
@@ -64,8 +64,8 @@
 #                     Default "auto". B210 USRP: 400 us, bladeRF: 0 us.
 #####################################################################
 [rf]
-tx_gain = 80
-rx_gain = 40
+tx_gain = ${enb.tx_gain}
+rx_gain = ${enb.rx_gain}
 
 device_name = ${enb.rf_dev_type}