fix incorrect dbus interface name

Previous code use bus_name as sd_bus_message_new_signal 4th input
parameter. It is incorrect. It is supposed to be dbus interface
name.

Change-Id: I03bf241fd705d39fd05b75230e33b67c5d77bf1c
Signed-off-by: Jia, Chunhui <chunhui.jia@linux.intel.com>
diff --git a/kcsbridged.c b/kcsbridged.c
index 9c58acd..cd7b583 100644
--- a/kcsbridged.c
+++ b/kcsbridged.c
@@ -340,7 +340,7 @@
 	if (len < 0 || handle_kcs_request(context, data, len))
 		goto out;
 
-	r = sd_bus_message_new_signal(context->bus, &msg, objPath, busName,
+	r = sd_bus_message_new_signal(context->bus, &msg, objPath, DBUS_INTF,
 				      "ReceivedMessage");
 	if (r < 0) {
 		MSG_ERR("Failed to create signal: %s\n", strerror(-r));