Add missing javadocs to satisfy linter

Test: TH
Change-Id: Ib2febede8b95bc74ef8d9b0f25b62320dde2cf84
diff --git a/service/src/com/android/server/L2capNetworkProvider.java b/service/src/com/android/server/L2capNetworkProvider.java
index f303cdc..814a068 100644
--- a/service/src/com/android/server/L2capNetworkProvider.java
+++ b/service/src/com/android/server/L2capNetworkProvider.java
@@ -650,6 +650,7 @@
             return thread;
         }
 
+        /** Create a tun interface configured for blocking i/o */
         @Nullable
         public ParcelFileDescriptor createTunInterface(String ifname) {
             final ParcelFileDescriptor fd;
@@ -673,6 +674,7 @@
             return fd;
         }
 
+        /** Create an L2capPacketForwarder and start forwarding */
         public L2capPacketForwarder createL2capPacketForwarder(Handler handler,
                 ParcelFileDescriptor tunFd, BluetoothSocket socket, boolean compressHeaders,
                 L2capPacketForwarder.ICallback cb) {