RandomX: don't restart mining threads when the seed changes

It helps to not loose huge pages when the seed changes (every 2048 blocks, ~2.8 days).

src/crypto/rx/RxQueue.cpp

@@ -154,6 +154,8 @@ void xmrig::RxQueue::backgroundInit()
             continue;
         }
 
+        // Update seed here again in case there was more than one item in the queue
+        m_seed = item.seed;
         m_state = STATE_IDLE;
         m_async->send();
     }