Fix f_enc_mcc_mnc() to return a properly encoded MCC/MNC triple octet.

With help from Daniel Willmann.

Change-Id: I99a5317e425d15acd463aa94c683676cacd54e0b
Related: OS#2754
diff --git a/library/BSSMAP_Templates.ttcn b/library/BSSMAP_Templates.ttcn
index cb6dde8..f452263 100644
--- a/library/BSSMAP_Templates.ttcn
+++ b/library/BSSMAP_Templates.ttcn
@@ -648,7 +648,7 @@
 }
 
 private function f_enc_mcc_mnc(GsmMcc mcc, GsmMnc mnc) return OCT3 {
-	return hex2oct(mcc[1] & mcc[0] & mnc[0] & mnc[2] & mnc[1]);
+	return hex2oct(mcc[1] & mcc[0] & mnc[2] & mcc[2] & mnc[1] & mnc[0]);
 }
 
 template BSSMAP_FIELD_CellIdentification_CGI ts_BSSMAP_CI_CGI(GsmMcc mcc, GsmMnc mnc, GsmLac lac, GsmCellId ci) := {