Cleanup warnings

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/mod.rs

src/arch/x86_64/interrupt/irq.rs

src/consts.rs

src/context/mod.rs

src/context/switch.rs

src/devices/uart_16550.rs

src/lib.rs

src/scheme/pipe.rs

src/sync/wait_condition.rs

src/sync/wait_map.rs

src/sync/wait_queue.rs

src/syscall/privilege.rs

src/syscall/process.rs