Remove TODO comment that was already done

The TODO is used to track to dynamically pass down the TTL from the
upstream interface. Remove it as it was already done in IpServer.

Test: No code changes
Change-Id: Idb12f82023315661f1bf4c767b9b7744a151e821
diff --git a/Tethering/src/android/net/ip/RouterAdvertisementDaemon.java b/Tethering/src/android/net/ip/RouterAdvertisementDaemon.java
index 775c36f..18c2171 100644
--- a/Tethering/src/android/net/ip/RouterAdvertisementDaemon.java
+++ b/Tethering/src/android/net/ip/RouterAdvertisementDaemon.java
@@ -129,9 +129,6 @@
         // Tethered traffic will have the hop limit properly decremented.
         // Consequently, set the hoplimit greater by one than the upstream
         // unicast hop limit.
-        //
-        // TODO: Dynamically pass down the IPV6_UNICAST_HOPS value from the
-        // upstream interface for more correct behaviour.
         static final byte DEFAULT_HOPLIMIT = 65;
 
         public boolean hasDefaultRoute;