RFR(M): 8131048: ppc: implement CRC32 intrinsic

[Lindenmaier, Goetz]

Hi,

Lutz implemented the CRC32 intrinsic for ppc.  So far, it's based on
the Power7 instructions.  Power8 might allow further optimizations.
Please review this change:
http://cr.openjdk.java.net/~goetz/webrevs/8131048-crc32/webrev.01/

We tested this with jck, jtreg and our benchmarks on aix, ppc64 and ppc64le.
Perormance improvements are seen especially for small jobs.

Best regards,
  Goetz