powerpc: drop MPC85xx_CDS platform support

powerpc: drop MPC85xx_CDS platform support

The MPC8541/8548/8555 Configurable Development System (CDS) were the
vehicle used to provide evaluation of the 1st e500-v2 CPUs around 2007.

Similar to the earlier MPC83xx-MDS systems we removed, the "brains"
exist on a PCI-X card, but additional connectors exist to the right of
the PCI-X slot, two structural metal pins are used to provide stability
in a vertical ATX mounting, and the CPU is now on a daughter-card vs. a
clamped down BGA.

Given the extra complexity and risk of connector damage, the 8548CDS
I had access to came pre-assembled in a basic white Antec case common
for that era, and I'm inclined to assume that was the default.

Power was typical "Pentium4" 2005 ATX - the main 20 pin connector went
to the PCI ATX form factor backplane, and the 4 pin black/yellow went
to the CPU card.

Like previous evaluation boards, they attempted to provide break-out
connectors for as many features as possible, and that made for a fairly
complex looking system.

In any case, these are over 15 years old, and fairly complex systems,
originally made for a small group of industry related people, and made
for use where quiet fan operation wasn't important.  Given that, it
makes sense to remove support from them in 2023.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230620043300.197546-3-paul.gortmaker@windriver.com