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

[Gui Cao]

The fix for JDK-8315743 touches MacroAssembler::load_reserved replacing `t0` with `dst`. But it missed change for the third case (that is `uint32`) if the switch in this assember function. We should also replace `t0` used in `zero_extend` with `dst`. @robehn can you help confirm this?

- [ ]  Run tier1 tests on qemu 8.1.50 with UseRVV (release)

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Commit messages:
 - 8322154: RISC-V: JDK-8315743 missed change in MacroAssembler::load_reserved

Changes: https://git.openjdk.org/jdk/pull/17117/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17117&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/jdk/pull/17117.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17117/head:pull/17117

PR: https://git.openjdk.org/jdk/pull/17117