hw/microblaze/s3adsp1800: Explicit CPU endianness

hw/microblaze/s3adsp1800: Explicit CPU endianness

By default the machine's CPU endianness is 'big' order
('little-endian' property set to %false).

This corresponds to the default when this machine was added;
see commits 6a8b1ae2020 "microblaze: Add petalogix s3a1800dsp
MMU linux ref-design." and 72b675caacf "microblaze: Hook into
the build-system." which added:

  [ "$target_cpu" = "microblaze" ] && target_bigendian=yes

Later commit 877fdc12b1a ("microblaze: Allow targeting
little-endian mb") added little-endian support, forgetting
to set the CPU endianness to little-endian. Not an issue
since this property was never used, but we will use it soon,
so explicit the endianness to get the expected behavior.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Message-Id: <20241105130431.22564-4-philmd@linaro.org>