target/ppc: Inline cpu_ldl_code() call in ppc_ldl_code()

In preparation of removing the cpu_ldl_code wrapper, inline it.

Get the runtime endianness with ppc_data_endian_env(), passing it
to cpu_ldl_code_mmu(). No need to swap versus qemu-system binary
anymore.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Anton Johansson <anjo@rev.ng>
Message-Id: <20260202210106.93257-12-philmd@linaro.org>