Minor optimisation to the step f_sync and f_close

Moved the code 'f_sync(&file);' ahead of 'f_close(&file);'.

examples/fatfs/fatfs_sample.c

@@ -50,8 +50,9 @@ void application_entry(void *arg)
     } else {
         printf("read error: %d\n", res);
     }
-    f_close(&file);
-
+    
     f_sync(&file);
+    
+    f_close(&file);
 }