Fixed sample rate not set correctly under slave I2S mode.

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@530 bbd45198-f89e-11dd-88c7-29a3b14d5316

bsp/stm32_radio/codec.c

@@ -481,7 +481,9 @@ static rt_err_t codec_control(rt_device_t dev, rt_uint8_t cmd, void *args)
         break;
 
     case CODEC_CMD_SAMPLERATE:
+        dev->close(dev);
         sample_rate(*((int*) args));
+        dev->open(dev,0);
         break;
 
     case CODEC_CMD_EQ: