[jdk26u] RFR: 8374056: RISC-V: Fix argument passing for the RiscvFlushIcache::flush

[Fei Yang]

Hi all,

This pull request contains a backport of commit [dc80ce7a](https://github.com/openjdk/jdk/commit/dc80ce7aec8e466a29fd4c94ee70c90a7244869f) from the [openjdk/jdk](https://git.openjdk.org/jdk) repository.

The commit being backported was authored by ikarostsin on 9 Feb 2026 and was reviewed by Fei Yang and Robbin Ehn.

Thanks!

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

Commit messages:
 - Backport dc80ce7aec8e466a29fd4c94ee70c90a7244869f

Changes: https://git.openjdk.org/jdk26u/pull/48/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk26u&pr=48&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8374056
  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk26u/pull/48.diff
  Fetch: git fetch https://git.openjdk.org/jdk26u.git pull/48/head:pull/48

PR: https://git.openjdk.org/jdk26u/pull/48