[jdk22] RFR: 8322154: RISC-V: JDK-8315743 missed change in MacroAssembler::load_reserved

[Gui Cao]

Clean backport which adds back missing code change in MacroAssembler::load_reserved in file src/hotspot/cpu/riscv/macroAssembler_riscv.cpp for https://bugs.openjdk.org/browse/JDK-8315743. This is a riscv-specific change, risk is low.

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Commit messages:
 - Backport 59073fa3eb7d04d9e0f08fbef70c9db6ffde296a

Changes: https://git.openjdk.org/jdk22/pull/19/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk22&pr=19&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8322154
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk22/pull/19.diff
  Fetch: git fetch https://git.openjdk.org/jdk22.git pull/19/head:pull/19

PR: https://git.openjdk.org/jdk22/pull/19