Fix compilation of acpi feature

src/acpi/aml/namedobj.rs

src/acpi/aml/namespace.rs

src/acpi/aml/parser.rs

src/acpi/aml/type1opcode.rs

src/acpi/aml/type2opcode.rs

src/acpi/dmar/mod.rs

src/acpi/fadt.rs

src/acpi/hpet.rs

src/acpi/madt.rs

src/acpi/mod.rs

src/acpi/rsdp.rs

src/acpi/rxsdt.rs

src/arch/x86_64/device/hpet.rs

src/arch/x86_64/device/mod.rs

src/arch/x86_64/ipi.rs

src/arch/x86_64/start.rs

src/arch/x86_64/stop.rs