target/riscv: Introduce mo_endian() helper

target/riscv: Introduce mo_endian() helper

mo_endian() returns the target endianness from DisasContext.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20251010155045.78220-13-philmd@linaro.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>