Share some more code between x86 and x86_64

Continuation of !273 (merged)

src/arch/aarch64/mod.rs

@@ -68,15 +68,6 @@ pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -
         options(noreturn)
     );
 }
-pub unsafe fn bootstrap_mem(bootstrap: &crate::Bootstrap) -> &'static [u8] {
-    use crate::memory::PAGE_SIZE;
-    use ::rmm::Arch;
-
-    core::slice::from_raw_parts(
-        CurrentRmmArch::phys_to_virt(bootstrap.base.start_address()).data() as *const u8,
-        bootstrap.page_count * PAGE_SIZE,
-    )
-}
 
 pub const KFX_SIZE: usize = 1024;