hw/microblaze: Propagate CPU endianness to microblaze_load_kernel()

hw/microblaze: Propagate CPU endianness to microblaze_load_kernel()

Pass vCPU endianness as argument so we can load kernels
with different endianness (different from the qemu-system-binary
builtin one).

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20241107012223.94337-3-philmd@linaro.org>