pdu_queue: add reset method to empty queue

lib/include/srslte/mac/pdu_queue.h

@@ -51,6 +51,8 @@ public:
 
   bool process_pdus();
 
+  void reset();
+
 private:
   const static int DEFAULT_POOL_SIZE = 64;             // Number of PDU buffers in total
   const static int MAX_PDU_LEN       = 150 * 1024 / 8; // ~ 150 Mbps

lib/src/mac/pdu_queue.cc

@@ -95,4 +95,12 @@ bool pdu_queue::process_pdus()
   return have_data;
 }
 
+void pdu_queue::reset()
+{
+  pdu_t* pdu;
+  while (pdu_q.try_pop(&pdu)) {
+    // nop
+  }
+}
+
 } // namespace srslte