ran_a_mgcp_codec_from_sc(): map GSM0808_SCT_CSD to CODEC_CLEARMODE

Change-Id: I4095124be8ffb293863f35bea440cd465048a9fd
Related: OS#6110, OS#4394
diff --git a/src/libmsc/ran_msg_a.c b/src/libmsc/ran_msg_a.c
index 37acedb..3788805 100644
--- a/src/libmsc/ran_msg_a.c
+++ b/src/libmsc/ran_msg_a.c
@@ -254,6 +254,8 @@
 		return CODEC_AMRWB_16000_1;
 	case GSM0808_SCT_HR6:
 		return CODEC_AMRWB_16000_1;
+	case GSM0808_SCT_CSD:
+		return CODEC_CLEARMODE;
 	default:
 		return CODEC_PCMU_8000_1;
 	}