remove old gdt/idt code

src/arch/x86_64/mod.rs

-use crate::{boot, error, smp::Cpu, warn};
+use crate::{error, smp::Cpu, warn};
 use x86_64::instructions::{self as ins, interrupts as int, random::RdRand};
 
 //
@@ -8,9 +8,6 @@ pub mod cpu;
 pub mod pmm;
 pub mod vmm;
 
-mod gdt;
-mod idt;
-
 //
 
 pub fn early_boot_cpu() {