Use the same *_tlb primitives as we use for ld1.

For linux-user, this hoists the set of helper_retaddr.  For softmmu,
hoists the computation of the current mmu_idx outside the loop,
fixes the endianness problem, and moves the main loop out of a
macro and into an inlined function.
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Tested-by: NLaurent Desnogues <laurent.desnogues@gmail.com>
Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
Message-id: 20181005175350.30752-9-richard.henderson@linaro.org
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>