WIP: vfs devices lazy init

src/arch/x86_64/cpu/ints.rs

src/driver/acpi/apic.rs

src/driver/acpi/hpet.rs

src/driver/acpi/mod.rs

src/driver/rtc.rs

src/main.rs

src/scheduler/kshell/shell.rs

src/scheduler/mod.rs

src/scheduler/timer.rs

src/util/atomic_map.rs

src/util/mod.rs

src/util/slice_read.rs

src/vfs/devices.rs

src/vfs/mod.rs