bts: Introduce mp_ipa_up_timeout parameter

Some test env may take more than 10 seconds to (re-)start a BTS, so
let's make it variable through this parameter.
For instance it was observed that running osmo-bts-sysmo through ssh
inside a sysmobts can sometimes take a good number of seconds (specially
because ssh connection can take a while to be established successfully).

Change-Id: Ieb046358d8266ac94bd7b9e916e85f84de3ad319
diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index 64c2510..cde9562 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -63,6 +63,8 @@
 	integer mp_ms_power_level_exp := 7;
 	integer mp_ms_actual_ta_exp := 0;
 	integer mp_timing_offset_256syms_exp := 512;
+	/* Time to wait for RSL conn from BTS during startup of test */
+	float mp_ipa_up_timeout := 10.0;
 }
 
 type record of RslChannelNr ChannelNrs;
@@ -296,7 +298,7 @@
 
 /* global init function */
 function f_init(charstring id := "BTS-Test") runs on test_CT {
-	timer T := 10.0;
+	timer T := mp_ipa_up_timeout;
 	g_AllChannels := {
 		/* TS 1..4: TCH/F */
 		valueof(ts_RslChanNr_Bm(1)), valueof(ts_RslChanNr_Bm(2)),