hw/microblaze: Deprecate big-endian petalogix-ml605 & xlnx-zynqmp-pmu

hw/microblaze: Deprecate big-endian petalogix-ml605 & xlnx-zynqmp-pmu

The petalogix-ml605 machine was explicitly added as little-endian only
machine in commit 00914b7d970 ("microblaze: Add PetaLogix ml605 MMU
little-endian ref design"). Mark the big-endian version as deprecated.

When the xlnx-zynqmp-pmu machine's CPU was added in commit 133d23b3ad1
("xlnx-zynqmp-pmu: Add the CPU and memory"), its 'endianness' property
was set to %true, thus wired in little endianness.

Both machine are included in the big-endian system binary, while their
CPU is working in little-endian. Unlikely to work as it. Deprecate now
as broken config so we can remove soon.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Anton Johansson <anjo@rev.ng>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Message-Id: <20241105130431.22564-3-philmd@linaro.org>