[jdk21u-dev] RFR: 8216437: PPC64: Add intrinsic for GHASH algorithm

[Suchismith Roy]

Hi all,

This pull request contains a backport of commit [cdad6d78](https://github.com/openjdk/jdk/commit/cdad6d788de4785c8dbf2710a86fdacb8d070565) from the [openjdk/jdk](https://git.openjdk.org/jdk) repository.

The commit being backported was authored by Suchismith Roy on 2 May 2025 and was reviewed by Martin Doerr and Amit Kumar.

Thanks!

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Commit messages:
 - Backport cdad6d788de4785c8dbf2710a86fdacb8d070565

Changes: https://git.openjdk.org/jdk21u-dev/pull/1789/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1789&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8216437
  Stats: 183 lines in 2 files changed: 181 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1789.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1789/head:pull/1789

PR: https://git.openjdk.org/jdk21u-dev/pull/1789