qemu: add castagnoli crc32c checksum algorithm

This adds the Castagnoli CRC32C algorithm, using the 0x11EDC6F41
polynomial.

This is extracted from the linux kernel cryptographic crc32.c module.

The algorithm is based on:

Castagnoli93: Guy Castagnoli and Stefan Braeuer and Martin Herrman
             "Optimization of Cyclic Redundancy-Check Codes with 24
              and 32 Parity Bits", IEEE Transactions on Communication,
              Volume 41, Number 6, June 1993

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
