Remove unused field.

src/workers/Hashrate.cpp

@@ -51,8 +51,7 @@ inline static const char *format(double h, char *buf, size_t size)
 Hashrate::Hashrate(size_t threads, xmrig::Controller *controller) :
     m_highest(0.0),
     m_threads(threads),
-    m_timer(nullptr),
-    m_controller(controller)
+    m_timer(nullptr)
 {
     m_counts     = new uint64_t*[threads];
     m_timestamps = new uint64_t*[threads];

src/workers/Hashrate.h

@@ -69,7 +69,6 @@ private:
     uint64_t** m_counts;
     uint64_t** m_timestamps;
     uv_timer_t *m_timer;
-    xmrig::Controller *m_controller;
 };