RFR: 8328812: Update and move siphash license

[Jesper Wilhelmsson]

Updated and moved the license file.

-------------

Commit messages:
 - 8328812: Update and move siphash license

Changes: https://git.openjdk.org/jdk/pull/18455/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18455&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8328812
  Stats: 4 lines in 1 file changed: 1 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/18455.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18455/head:pull/18455

PR: https://git.openjdk.org/jdk/pull/18455