kick off link discovery only for available devices

Change-Id: Ibdec36f5f44a84fa692250d84fdb21c7ddaa42b6
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 d04213a..044dbc8 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
@@ -101,7 +101,7 @@
         masterService.addListener(roleListener);
 
         LinkDiscovery ld;
-        for (Device device : deviceService.getDevices()) {
+        for (Device device : deviceService.getAvailableDevices()) {
             ld = new LinkDiscovery(device, packetSevice, masterService,
                               providerService, useBDDP);
             discoverers.put(device.id(), ld);