ruby: Check all VNETs for injection in garnet NetworkInterface

The NetworkInterface wakeup currently iterates over all VNETs and breaks the
loop if a VNET is unable to allocate a VC. This can cause a deadlock if a
lower numbered VNET is unable to allocate a VC while a higher numbered VNET
has idle VCs. This seems like a bug as Garnet 1.0 uses a while loop over an
if-statement, suggesting the break was intended for this while loop. This
patch removes the break statement, which allows up to one message to be
dequeued from a VNET and injected into the network.

src/mem/ruby/network/garnet2.0/NetworkInterface.cc

@@ -159,8 +159,6 @@ NetworkInterface::wakeup()
             msg_ptr = b->peekMsgPtr();
             if (flitisizeMessage(msg_ptr, vnet)) {
                 b->dequeue(curTime);
-            } else {
-                break;
             }
         }
     }