target/arm: Adjust gen_aa32_{ld, st}_i32 for align+endianness

target/arm: Adjust gen_aa32_{ld, st}_i32 for align+endianness

Create a finalize_memop function that computes alignment and
endianness and returns the final MemOp for the operation.

Split out gen_aa32_{ld,st}_internal_i32 which bypasses any special
handling of endianness or alignment.  Adjust gen_aa32_{ld,st}_i32
so that s->be_data is not added by the callers.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210419202257.161730-12-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>