enb.py: increase zmq trx timeout to 4000ms

with many parallel jobs running on one machine we should
relax the timeout a bit to avoid false positives.

Change-Id: Ib32a07559bd5a4b0165f6d3431c5ac57cc050f44
diff --git a/src/osmo_gsm_tester/obj/enb.py b/src/osmo_gsm_tester/obj/enb.py
index 15a0033..99d43f8 100644
--- a/src/osmo_gsm_tester/obj/enb.py
+++ b/src/osmo_gsm_tester/obj/enb.py
@@ -266,7 +266,7 @@
         else:
             ul_rem_addr = self.ue.addr()
 
-        rf_dev_args = 'fail_on_disconnect=true'
+        rf_dev_args = 'fail_on_disconnect=true,log_trx_timeout=true,trx_timeout_ms=4000'
         idx = 0
         cell_list = cfg_values['enb']['cell_list']
         # Define all 8 possible RF ports (2x CA with 2x2 MIMO)