Merge pull request #4226 from redocCheng/master

解决添加RT_USING_MTD_NOR编译报错的问题

components/drivers/spi/spi_flash.h

@@ -6,11 +6,14 @@
  * Change Logs:
  * Date           Author       Notes
  * 2016/5/20      bernard      the first version
+ * 2020/1/7       redoc        add include
  */
 
 #ifndef SPI_FLASH_H__
 #define SPI_FLASH_H__
 
+#include <rtdevice.h>
+
 struct spi_flash_device
 {
     struct rt_device                flash_device;