add ports back to discoverer after a device has
gone offline and come back.

Change-Id: I524e25570f9eee8870e97ed09612c423e0cf9588
diff --git a/providers/lldp/src/main/java/org/onosproject/provider/lldp/impl/LldpLinkProvider.java b/providers/lldp/src/main/java/org/onosproject/provider/lldp/impl/LldpLinkProvider.java
index 94abeba..668d59c 100644
--- a/providers/lldp/src/main/java/org/onosproject/provider/lldp/impl/LldpLinkProvider.java
+++ b/providers/lldp/src/main/java/org/onosproject/provider/lldp/impl/LldpLinkProvider.java
@@ -570,7 +570,7 @@
                 case DEVICE_AVAILABILITY_CHANGED:
                     if (deviceService.isAvailable(deviceId)) {
                         log.debug("Device up {}", deviceId);
-                        updateDevice(device);
+                        updateDevice(device).ifPresent(ld -> updatePorts(ld, deviceId));
                     } else {
                         log.debug("Device down {}", deviceId);
                         removeDevice(deviceId);