Fix warnings

src/acpi/hpet.rs

src/acpi/madt.rs

src/acpi/mod.rs

src/acpi/rsdp.rs

src/arch/x86_64/device/cpu.rs

src/arch/x86_64/device/hpet.rs

src/arch/x86_64/idt.rs

src/arch/x86_64/rmm.rs

src/arch/x86_64/start.rs

src/context/memory.rs

src/debugger.rs

src/devices/graphical_debug/mod.rs

src/lib.rs

src/scheme/proc.rs

src/syscall/futex.rs

src/syscall/process.rs