Fix using asm on newer nightlies

See merge request redox-os/hwio!4

The `asm` macro will finally be stabilized in 1.59.0. It must now be
imported from the `arch` module.

Signed-off-by: Tim Crawford <tcrawford@system76.com>

Replace unaligned ref with raw pointer

See merge request redox-os/hwio!3

Unaligned references currently create a warning, and will be a hard
error in the future. Use the `addr_of!()` (Rust 1.51.0+) macro to create
a raw pointer without creating an intermediate reference.

Deprecate `Mmio::new()` as it is unsound. These values should only be
constructed by transmuting memory.

Signed-off-by: Tim Crawford <tcrawford@system76.com>

Signed-off-by: Tim Crawford <tcrawford@system76.com>

Fix or silence clippy warnings

See merge request !2

Fix:
- clippy::redundant_field_names

Silence:
- clippy::new_without_default
- clippy::uninit_assumed_init

Signed-off-by: Tim Crawford <tcrawford@system76.com>

Fix compiling on nightly

See merge request !1

llvm_asm is deprecrated and may be removed. Replace it with the new asm.

Signed-off-by: Tim Crawford <tcrawford@system76.com>

const_fn was removed. New const_fn_* features were added for tracking
specific implementations.

Fixes compiling on newer toolchains.

Signed-off-by: Tim Crawford <tcrawford@system76.com>