refactor(cpus): convert print_errata_status to C

The function is called in a fully initialised C environment and calls
into other C functions. The Aarch differences are minimal and are hidden
by the pre-existing headers. Converting it results into cleaner code
that is the same across both Aarch64 and Aarch32.

To avoid having to do very ugly pointer arithmetic, define a C struct
for the cpu_ops for both Aarch64 and Aarch32.

Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: Idc07c4064e03143c88a4a0e2d10ceda70ba19a50