drivers: use new ringbuffer namespace everywhere

src/drivers/airspeed/airspeed.cpp

@@ -128,7 +128,7 @@ Airspeed::init()
 		goto out;
 
 	/* allocate basic report buffers */
-	_reports = new RingBuffer(2, sizeof(differential_pressure_s));
+	_reports = new ringbuffer::RingBuffer(2, sizeof(differential_pressure_s));
 	if (_reports == nullptr)
 		goto out;
 

src/drivers/airspeed/airspeed.h

@@ -109,7 +109,7 @@ public:
 	virtual void	print_info();
 
 private:
-	RingBuffer		*_reports;
+	ringbuffer::RingBuffer		*_reports;
 	perf_counter_t		_buffer_overflows;
 
 	/* this class has pointer data members and should not be copied */