refactor: slightly refactor amd64

src/platform/um/entry.zig

@@ -3,8 +3,6 @@ const b = @import("base");
 pub const std_options = b.std_options;
 pub const panic = b.panic;
 
-pub const rtl = @import("rtl");
-
 const c = @cImport({
     @cInclude("SDL.h");
     @cInclude("signal.h");

src/platform/um/impl.zig

@@ -37,8 +37,6 @@ pub const GlobalState = struct {
 pub var global_state: GlobalState = undefined;
 pub threadlocal var my_cpu: *ke.Cpu = undefined;
 
-pub fn devices_init() void {}
-
 pub fn debug_write(char: u8) void {
     _ = linux.write(linux.STDERR_FILENO, @ptrCast(&char), 1);
 }