adding option for using blocking spi transfer

bsp/imxrt/libraries/drivers/drv_spi.c

@@ -347,7 +347,11 @@ static rt_uint32_t spixfer(struct rt_spi_device *device, struct rt_spi_message *
 
     if(RT_FALSE == spi->dma_flag)
     {
+#ifdef(BSP_USING_BLOCKING_SPI)
+        status = LPSPI_MasterTransferBlocking(spi->base, &transfer);
+#else
         status = LPSPI_MasterTransferNonBlocking(spi->base, &spi->spi_normal, &transfer);
+#endif
     }
     else
     {