missing endian swap for remainder case

[tstack]

The following lines are reading from the data without doing the endian swap:

https://github.com/k0dai/spookyhash/blob/b9954b4b72fbc9424c5f59b345c51b25ad925b95/src/spookyhash.c#L178-L179

There's a couple of other lines in this remainder case as well that are missing the swap.

Without these swaps, the results are different. I was testing on an s390x and getting correct results in some cases, but not others.