The ic_scr_key_valid field indicates whether the ICache scrambling key
is valid.
CPUCTRL is also renamed CPUCTRLSTS as it contains both control and
status bits.
Convert the documentation to restructured text. It looks slightly
different to the previous Word document, but can better be handled by
source control. It also automatically handles the versioning.
To build it:
python -m venv venv
source venv/bin/activate
pip install -r requirements.txt
make html
make latexpdf
