mgcp_stat: Don't print osmux stats if it is off

Otherwise we get Osmux stats during a session using RTP, which is
confusing.

Change-Id: I6fcd680a073fbf8769488ffa2b2b32098c87edf4
diff --git a/tests/mgcp/mgcp_test.c b/tests/mgcp/mgcp_test.c
index 38a0a46..e1e6290 100644
--- a/tests/mgcp/mgcp_test.c
+++ b/tests/mgcp/mgcp_test.c
@@ -314,7 +314,9 @@
 
 #define DLCX_RET \
 	"250 7 OK\r\n" \
-	"P: PS=0, OS=0, PR=0, OR=0, PL=0, JI=0\r\n" \
+	"P: PS=0, OS=0, PR=0, OR=0, PL=0, JI=0\r\n"
+
+ #define DLCX_RET_OSMUX DLCX_RET \
 	"X-Osmo-CP: EC TI=0, TO=0\r\n"
 
 #define RQNT \