部分函数从返回值为Result<<>,i32>修改为Result<<>,SystemError> (#210)

* 将Result<<>,i32>替换为Result<<>,SystemError>
* bugfix: 显示双缓冲区初始化的时候，连续注册了两次Video Softirq的问题。

Co-authored-by: longjin <longjin@RinGoTek.cn>

kernel/src/driver/timers/rtc/rtc.rs

@@ -1,6 +1,6 @@
 use crate::{
     arch::interrupt::{cli, sti},
-    include::bindings::bindings::{io_in8, io_out8},
+    include::bindings::bindings::{io_in8, io_out8}, syscall::SystemError,
 };
 
 pub struct RtcTime {
@@ -30,7 +30,7 @@ impl RtcTime {
     ///
     ///@param self time结构体
     ///@return int 成功则为0
-    pub fn get(&mut self) -> Result<i32, i32> {
+    pub fn get(&mut self) -> Result<i32, SystemError> {
         // 为防止中断请求打断该过程，需要先关中断
         cli();
         //0x0B