Print all parent drivers

Change-Id: Iceb343f33c81c4fb0d8548a0ac12eb247249323b
diff --git a/cli/src/main/java/org/onosproject/cli/net/DriversListCommand.java b/cli/src/main/java/org/onosproject/cli/net/DriversListCommand.java
index 1535609..3ae2b8e 100644
--- a/cli/src/main/java/org/onosproject/cli/net/DriversListCommand.java
+++ b/cli/src/main/java/org/onosproject/cli/net/DriversListCommand.java
@@ -69,12 +69,13 @@
         if (outputJson()) {
             json(driver);
         } else {
-            Driver parent = driver.parent();
-            print(FMT, driver.name(), parent != null ? parent.name() : "none",
-                    driver.manufacturer(), driver.hwVersion(), driver.swVersion());
-            driver.behaviours().forEach(b -> print(FMT_B, b.getCanonicalName(),
-                    driver.implementation(b).getCanonicalName()));
-            driver.properties().forEach((k, v) -> print(FMT_P, k, v));
+            driver.parents().forEach(parent -> {
+                print(FMT, driver.name(), parent != null ? parent.name() : "none",
+                           driver.manufacturer(), driver.hwVersion(), driver.swVersion());
+                driver.behaviours().forEach(b -> print(FMT_B, b.getCanonicalName(),
+                                                       driver.implementation(b).getCanonicalName()));
+                driver.properties().forEach((k, v) -> print(FMT_P, k, v));
+            });
         }
     }