computeCI(): Constify param and pass it as reference

Change-Id: Icba5fce57c858bd16196ae3012c100c7e4134335
diff --git a/Transceiver52M/sigProcLib.cpp b/Transceiver52M/sigProcLib.cpp
index fa8a407..7169a15 100644
--- a/Transceiver52M/sigProcLib.cpp
+++ b/Transceiver52M/sigProcLib.cpp
@@ -1462,7 +1462,7 @@
  * by comparing the "ideal" training sequence with the actual one.
  */
 static float computeCI(const signalVector *burst, const CorrelationSequence *sync,
-                       float toa, int start, complex xcorr)
+                       float toa, int start, const complex &xcorr)
 {
   float S, C;
   int ps;