fix:修复报错

luat/include/luat_mcu.h

@@ -11,4 +11,5 @@ long luat_mcu_ticks(void);
 
 uint32_t luat_mcu_hz(void);
 
-#endif
+#endif
+

luat/modules/luat_lib_spi.c

@@ -146,7 +146,7 @@ int luat_spi_soft_recv(luat_espi_t *espi, char *buff, size_t len)
     return 0;
 }
 
-int luat_spi_soft_xfer(luat_espi_t *espi, char *send_buff, char* recv_buff, size_t len)
+int luat_spi_soft_xfer(luat_espi_t *espi, const char *send_buff, char* recv_buff, size_t len)
 {
     size_t i = 0;
     if (espi->cs != Luat_GPIO_MAX_ID)