[jdk21u] RFR: 8320564: RISC-V: Minimal build failed after JDK-8316592

[ArsenyBochkarev]

Fix for initial implementation of `_poly1305_processBlocks`. JBS issue: https://bugs.openjdk.org/browse/JDK-8320564

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Depends on: https://git.openjdk.org/jdk21u/pull/390

Commit messages:
 - Backport 864b39a89398731bfde9af10c3d7797ff5d05760

Changes: https://git.openjdk.org/jdk21u/pull/404/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21u&pr=404&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8320564
  Stats: 42 lines in 2 files changed: 21 ins; 21 del; 0 mod
  Patch: https://git.openjdk.org/jdk21u/pull/404.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u.git pull/404/head:pull/404

PR: https://git.openjdk.org/jdk21u/pull/404