GSMTAP: add missing parameter docstrings

Change-Id: I774b89e0358bdcf7c71c7fd9c9940f634a7d3822
diff --git a/src/core/gsmtap_util.c b/src/core/gsmtap_util.c
index 33667c3..1d5fbab 100644
--- a/src/core/gsmtap_util.c
+++ b/src/core/gsmtap_util.c
@@ -471,8 +471,10 @@
 
 
 /*! Open GSMTAP source socket, connect and register osmo_fd
- *  \param[in] host host name or IP address in string format
- *  \param[in] port UDP port number in host byte order
+ *  \param[in] local_host IP address in string format
+ *  \param[in] local_port UDP port number in host byte order
+ *  \param[in] rem_host host name or IP address in string format
+ *  \param[in] rem_port UDP port number in host byte order
  *  \param[in] ofd_wq_mode Register \ref osmo_wqueue (1) or not (0)
  *  \return callee-allocated \ref gsmtap_inst
  *