target/openrisc: Replace MO_TE -> MO_BE

target/openrisc: Replace MO_TE -> MO_BE

We only build the OpenRISC targets using big endianness order:

  $ git grep TARGET_BIG_ENDIAN configs/targets/or1k-*
  configs/targets/or1k-linux-user.mak:2:TARGET_BIG_ENDIAN=y
  configs/targets/or1k-softmmu.mak:2:TARGET_BIG_ENDIAN=y

Therefore the MO_TE definition always expands to MO_BE. Use the
latter to simplify.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20251010070702.51484-12-philmd@linaro.org>