chore: adjust warning and remove unused imports

kernel/src/arch/riscv/entry.rs

@@ -1,5 +1,5 @@
 use crate::arch::init_early_console;
-use crate::arch::layout::{mmap_phys_to_virt, zero_bss, KERNEL_OFFSET};
+use crate::arch::layout::{mmap_phys_to_virt, zero_bss};
 use crate::arch::vspace::{setup_kernel_paging, setup_memory};
 use crate::entry::{rust_main, HART_ID};
 use crate::plat::console::mute_console;

kernel/src/arch/riscv/trap.rs

@@ -1,6 +1,5 @@
 use crate::entry::HART_ID;
 use crate::plat::console::CONSOLE;
-use cfg_if::cfg_if;
 use log::trace;
 use riscv::register::scause::{Interrupt as I, Trap as T};
 use riscv::register::stvec::TrapMode;

kernel/src/main.rs

@@ -16,7 +16,8 @@
 #![feature(custom_test_frameworks)]
 #![test_runner(test_runner::runner)]
 #![reexport_test_harness_main = "test_main"]
-#![cfg_attr(test, allow(dead_code))]
+// no noisy dead_code warnings
+#![allow(dead_code)]
 
 #[macro_use]
 extern crate static_assertions;