mkl26z4 peripheral access crate

Autogenerated from SVD file found at https://github.com/platformio/platform-teensy (boards/teensylc.json pointint to MKL26Z4.svd); file can be found in many public places.

Generated using https://crates.io/crates/svd2rust and https://crates.io/crates/form (see Makefile).

Run make to regen (touch MKL2Z64.svd might be necessary).

TODO: is it possible to just have the svd file in repo and generate glue from build.rs?