RFR: 8323110: Eliminate -Wparentheses warnings in ppc code

[Kim Barrett]

Please review this trivial change to eliminate a -Wparentheses warning.
This involved simply adding parentheses to make the implicit operator
precedence explicit.

Testing: Locally (linux-x64) cross-compiled for linux-ppc64le. Also ran GHA with
-Wparentheses enabled along with this and other changes needed to make that
work.

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Commit messages:
 - fix -Wparentheses warnings in ppc code

Changes: https://git.openjdk.org/jdk/pull/17293/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17293&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8323110
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/17293.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17293/head:pull/17293

PR: https://git.openjdk.org/jdk/pull/17293