Introduce log fmt helpers LOGPENDP and LOGPCONN

Let's define macro once and use it everywhere instead of passing endp
information in different ways everywhere. Furthermore, use conn whenever
appropiate to have more information.

Change-Id: I1c49b1eb16bc5f1010376da5cf407ca6e31d81f2
diff --git a/src/libosmo-mgcp/mgcp_sdp.c b/src/libosmo-mgcp/mgcp_sdp.c
index 02b9695..6b41f50 100644
--- a/src/libosmo-mgcp/mgcp_sdp.c
+++ b/src/libosmo-mgcp/mgcp_sdp.c
@@ -376,7 +376,7 @@
 
 	talloc_free(tmp_ctx);
 
-	LOGP(DLMGCP, LOGL_NOTICE,
+	LOGPCONN(conn->conn, DLMGCP, LOGL_NOTICE,
 	     "Got media info via SDP: port:%d, addr:%s, duration:%d, payload-types:",
 	     ntohs(rtp->rtp_port), inet_ntoa(rtp->addr),
 	     rtp->packet_duration_ms);
@@ -571,6 +571,6 @@
 	return 0;
 
 buffer_too_small:
-	LOGP(DLMGCP, LOGL_ERROR, "SDP messagebuffer too small\n");
+	LOGPCONN(conn->conn, DLMGCP, LOGL_ERROR, "SDP messagebuffer too small\n");
 	return -1;
 }