srs: Convert additional_args attr to list to allow combining different params

Change-Id: I4b371332cd6fbe11b98c85c79a6f8fdcc776a57b
diff --git a/src/osmo_gsm_tester/obj/enb_srs.py b/src/osmo_gsm_tester/obj/enb_srs.py
index 9dc8113..1b23172 100644
--- a/src/osmo_gsm_tester/obj/enb_srs.py
+++ b/src/osmo_gsm_tester/obj/enb_srs.py
@@ -176,7 +176,9 @@
         self.enable_pcap = util.str2bool(values['enb'].get('enable_pcap', 'false'))
         config.overlay(values, dict(enb={'enable_pcap': self.enable_pcap}))
 
-        self._additional_args = values['enb'].get('additional_args', '').split()
+        self._additional_args = []
+        for add_args in values['enb'].get('additional_args', []):
+            self._additional_args += add_args.split()
 
         # We need to set some specific variables programatically here to match IP addresses:
         if self._conf.get('rf_dev_type') == 'zmq':