Reading ARM docs

I'm reading up for work-related reasons.  On our platform we use
ARM Cortex A53, and my goal is to enable some memory-related CPU
features.

This is a great opportunity to learn something new, and I see how it dusts
off some knowledge I gained back at uni.  I'm happy to have the
opportunity review knowledge and use it in practice!

I've created a new text file, and indexed it in the top level page as
"ARM Cortext A53 notes".

It is definitely not intended as a guide, rather as a tracking of my
personal advancement in learning about these topics.