Merge r226837 & r226839 from head:

r226837:
Improve AES-NI performance for AES-XTS:
- Operate on uint64_t types when doing XORing, etc. instead of uint8_t.
- Don't bzero() temporary block for every AES block. Do it once for entire
  data block.
- AES-NI is available only on little endian architectures. Simplify code
  that takes block number from IV.

r226839:
Update Copyright.