target/arm: Adjust gen_aa32_{ld, st}_i64 for align+endianness

target/arm: Adjust gen_aa32_{ld, st}_i64 for align+endianness

Adjust the interface to match what has been done to the
TCGv_i32 load/store functions.

This is less obvious, because at present the only user of
these functions, trans_VLDST_multiple, also wants to manipulate
the endianness to speed up loading multiple bytes.  Thus we
retain an "internal" interface which is identical to the
current gen_aa32_{ld,st}_i64 interface.

The "new" interface will gain users as we remove the legacy
interfaces, gen_aa32_ld64 and gen_aa32_st64.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210419202257.161730-15-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>