Move AMR defintions out of OSMUX_Types to its own file

This way they can be used without the need to import OSMUX related
modules.

Change-Id: I0edfbb7359516ba77180afab18c3e1ffb2d0c927
diff --git a/mgw/MGCP_Test.ttcn b/mgw/MGCP_Test.ttcn
index 6d23c10..cbc22a6 100644
--- a/mgw/MGCP_Test.ttcn
+++ b/mgw/MGCP_Test.ttcn
@@ -24,6 +24,7 @@
 	import from OSMUX_CodecPort all;
 	import from OSMUX_CodecPort_CtrlFunct all;
 	import from OSMUX_Emulation all;
+	import from AMR_Types all;
 	import from IPL4asp_Types all;
 	import from General_Types all;
 	import from Native_Functions all;