MS5611: Use the right locking mechanism on Pixracer

src/drivers/ms5611/ms5611_spi.cpp

@@ -143,6 +143,11 @@ MS5611_SPI::~MS5611_SPI()
 int
 MS5611_SPI::init()
 {
+	// Sharing a bus with NuttX drivers
+#if defined (CONFIG_ARCH_BOARD_PX4FMU_V4)
+	set_lockmode(SPI::LOCK_THREADS);
+#endif
+
 	int ret;
 
 	ret = SPI::init();