hw/s390x: Access MemoryRegion with MemOp

hw/s390x: Access MemoryRegion with MemOp

The memory_region_dispatch_{read|write} operand "unsigned size" is
being converted into a "MemOp op".

Convert interfaces by using no-op size_memop.

After all interfaces are converted, size_memop will be implemented
and the memory_region_dispatch_{read|write} operand "unsigned size"
will be converted into a "MemOp op".

As size_memop is a no-op, this patch does not change any behaviour.

Signed-off-by: Tony Nguyen <[email protected]>
Reviewed-by: Richard Henderson <[email protected]>
Reviewed-by: Cornelia Huck <[email protected]>
Message-Id: <2f41da26201fb9b0339c2b7fde34df864f7f9ea8.1566466906[email protected]>
Signed-off-by: Richard Henderson <[email protected]>