target/arm: Require alignment for load exclusive

target/arm: Require alignment for load exclusive

According to the ARM ARM exclusive loads require the same alignment as
exclusive stores. Let's update the memops used for the load to match
that of the store. This adds the alignment requirement to the memops.

Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20170815145714.17635-4-richard.henderson@linaro.org
[rth: Require 16-byte alignment for 64-bit LDXP.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>