Fix warnings

src/acpi/hpet.rs

@@ -3,7 +3,7 @@ use core::{mem, ptr};
 use core::intrinsics::{volatile_load, volatile_store};
 
 use crate::memory::Frame;
-use crate::paging::{KernelMapper, PhysicalAddress, Page, PageFlags, VirtualAddress};
+use crate::paging::{KernelMapper, PhysicalAddress, PageFlags};
 use crate::paging::entry::EntryFlags;
 
 use super::sdt::Sdt;

src/context/context.rs

@@ -1,7 +1,7 @@
 use alloc::{
     boxed::Box,
     collections::VecDeque,
-    string::{String, ToString},
+    string::{String},
     sync::Arc,
     vec::Vec,
 };

src/syscall/fs.rs

@@ -10,7 +10,7 @@ use crate::scheme::{self, FileHandle};
 use crate::syscall::data::{Packet, Stat};
 use crate::syscall::error::*;
 use crate::syscall::flag::*;
-use crate::syscall;
+
 
 pub fn file_op(a: usize, fd: FileHandle, c: usize, d: usize) -> Result<usize> {
     let (file, pid, uid, gid) = {