refactor(cpus): move cpu_ops field defines to a header

The cpu_macros.S file is loaded with lots of definitions for the cpu_ops
structure. However, since they are defined as .equ directives they are
inaccessible for C code. Convert them to #defines, put them into order,
refactor them for readability, and extract them to a separate file to
make this possible.

This has the benefit of removing some Aarch differences and a lot of
duplicate code.

Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: I72861794b6c9131285a9297d5918822ed718b228
8 files changed