adc驱动优化，支持多通道连续读

components/drivers/misc/adc.c

@@ -27,9 +27,9 @@ static rt_size_t _adc_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_
     struct rt_adc_device *adc = (struct rt_adc_device *)dev;
     rt_uint32_t *value = (rt_uint32_t *)buffer;
 
-    for (i = 0; i < size; i += sizeof(int))
+    for (i = 0; i < size; i += sizeof(int), pos++)
     {
-        result = adc->ops->convert(adc, pos + i, value);
+        result = adc->ops->convert(adc, pos, value);
         if (result != RT_EOK)
         {
             return 0;