Improve GPRS logging

* log xid type as string instead of int
* log packet encryption status, algorithm and IOV-UI in debug mode
* print encryption parameters when dumping llme via vty
* log key propagation from MM to LLC

Related: OS#1794
Change-Id: I30c38fdeb0b88bb39bdb9928851300bc79e6aec6
diff --git a/openbsc/src/gprs/gprs_gb_parse.c b/openbsc/src/gprs/gprs_gb_parse.c
index f11d93a..9befa39 100644
--- a/openbsc/src/gprs/gprs_gb_parse.c
+++ b/openbsc/src/gprs/gprs_gb_parse.c
@@ -398,7 +398,7 @@
 
 	/* parse LLC */
 	rc = gprs_llc_hdr_parse(ghp, llc, llc_len);
-	gprs_llc_hdr_dump(ghp);
+	gprs_llc_hdr_dump(ghp, NULL);
 	if (rc != 0) {
 		LOGP(DLLC, LOGL_NOTICE, "Error during LLC header parsing\n");
 		return 0;