add mutex to codecs

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@10360 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/include/switch_module_interfaces.h

@@ -544,6 +544,7 @@ struct switch_codec {
 	/*! private data for the codec module to store handle specific info */
 	void *private_info;
 	switch_payload_t agreed_pt;
+	switch_mutex_t *mutex;
 };
 
 /*! \brief A table of settings and callbacks that define a paticular implementation of a codec */