application/demo_cidu: add tips to press any key to trigger uart receive interrupt

Signed-off-by: dongyongtao <dongyongtao@nucleisys.com>

application/baremetal/demo_cidu/demo_cidu.c

@@ -150,7 +150,7 @@ int main(void)
         __enable_irq();
         // Enable uart0 receive interrupt
         uart_enable_rxint(SOC_DEBUG_UART);
-
+        printf("You can press any key now to trigger uart receive interrupt, and only the first hart claims it\n");
         boothart_ready = 1;
         ret = boot_hart_main(hartid);
     } else { // other harts