SVD-based device crates for ARM microcontrollers/processors

Each subdirectory contains a crate for a specific ARM microcontroller or processor.

Most crates have been generated as follows:

1. Obtain the SVD file from a vendor-specific source (should be documented in the README.md of the crate).

2. Convert to Rust code using svd2rust -i DEVICE.svd (svd2rust docs).

3. Unroll using form -i lib.rs -o src (form docs).

4. Craft a Cargo.toml.

5. Beautify using cargo fmt.