Fix compile errors.

kernel/src/arch/mipsel/cpu.rs

@@ -2,7 +2,6 @@ use mips::registers::cp0;
 use mips::instructions;
 use crate::consts::MAX_CPU_NUM;
 use core::ptr::{read_volatile, write_volatile};
-use mips::registers::cp0;
 
 static mut STARTED: [bool; MAX_CPU_NUM] = [false; MAX_CPU_NUM];
 

kernel/src/arch/mipsel/mod.rs

@@ -1,4 +1,3 @@
-pub mod compiler_rt;
 pub mod consts;
 pub mod cpu;
 pub mod driver;