drivers: audio: Close MQ in cxd56 SRC

Closes the message queue file handle when the sample
rate converter is de-initialized.

Signed-off-by: Tobias Johansson <tobias.johansson@sony.com>

drivers/audio/cxd56_src.c

@@ -529,6 +529,8 @@ int cxd56_src_deinit(void)
     file_close(&dump_file_post);
 #endif
 
+  file_mq_close(&g_src.mq);
+
   return OK;
 }