Revert "drop (now) unused code"

This reverts commit 2b30cbdfa83c20045ef92f53e88441dda185591b.

Reason for revert: Older versions of osmo-msc were actually calling map_codec_to_pt().

Change-Id: Ifff31012b327d40ed0b1559d5cf4f320784a4061
Related: https://jenkins.osmocom.org/jenkins/job/Osmocom-build-tags-against-master/1792/console
diff --git a/include/osmocom/mgcp_client/mgcp_client.h b/include/osmocom/mgcp_client/mgcp_client.h
index e1748a6..1d33690 100644
--- a/include/osmocom/mgcp_client/mgcp_client.h
+++ b/include/osmocom/mgcp_client/mgcp_client.h
@@ -119,5 +119,9 @@
 }
 
 enum mgcp_codecs map_str_to_codec(const char *str);
+unsigned int map_codec_to_pt(const struct ptmap *ptmap, unsigned int ptmap_len,
+			     enum mgcp_codecs codec);
+enum mgcp_codecs map_pt_to_codec(struct ptmap *ptmap, unsigned int ptmap_len,
+				 unsigned int pt);
 
 const char *mgcp_client_name(const struct mgcp_client *mgcp);