Fix a couple of unused import warnings

src/context/arch/aarch64.rs

@@ -6,7 +6,7 @@ use crate::{
 };
 use core::{mem, mem::offset_of, ptr, sync::atomic::AtomicBool};
 use spin::Once;
-use syscall::{EnvRegisters, Error, Result, ENOMEM};
+use syscall::{EnvRegisters, Result};
 
 /// This must be used by the kernel to ensure that context switches are done atomically
 /// Compare and exchange this to true when beginning a context switch on any CPU

src/context/arch/riscv64.rs

@@ -1,8 +1,5 @@
 use crate::{
-    arch::interrupt::InterruptStack,
-    context::context::Kstack,
-    memory::{KernelMapper, RmmA},
-    percpu::PercpuBlock,
+    arch::interrupt::InterruptStack, context::context::Kstack, memory::RmmA, percpu::PercpuBlock,
     syscall::FloatRegisters,
 };
 use core::{mem::offset_of, sync::atomic::AtomicBool};