target/arm: Drop copies in gen_sve_{ldr,str}

target/arm: Drop copies in gen_sve_{ldr,str}

Since we now get TEMP_TB temporaries by default, we no longer
need to make copies across these loops.  These were the only
uses of new_tmp_a64_local(), so remove that as well.

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