cosmetic: Use msgb_hexdump*() rather than manual osmo_hexdump() on msg

This requires libosmocore Change-Id I98e85397fb541ee0fd711f2e1852f63f3bb87359

Change-Id: Ieeb97a9f1eba2fdef84294b8c8c7ac0984ae5c70
diff --git a/src/libcommon/gsup_test_client.c b/src/libcommon/gsup_test_client.c
index 963b495..8b6199e 100644
--- a/src/libcommon/gsup_test_client.c
+++ b/src/libcommon/gsup_test_client.c
@@ -220,7 +220,7 @@
 	struct imsi_op *io;
 	int rc;
 
-	DEBUGP(DLGSUP, "Rx GSUP %s\n", osmo_hexdump(msgb_l2(msg), msgb_l2len(msg)));
+	DEBUGP(DLGSUP, "Rx GSUP %s\n", msgb_hexdump(msg));
 
 	rc = osmo_gsup_decode(msgb_l2(msg), msgb_l2len(msg), &gsup_msg);
 	if (rc < 0)