RFR: 8352022: RISC-V: Support Zfa fminm_h/fmaxm_h for float16

[Anjian-Wen]

For the support of float16, add the Zfa fminm/fmaxm with the type of float16
this is still a draft which need test which related to https://bugs.openjdk.org/browse/JDK-8345298

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Commit messages:
 - RISCV: support Zfa fminm_h/fmaxm_h with type float16
 - RISC-V: support Zfa fminm_h/fmaxm_h with type float16

Changes: https://git.openjdk.org/jdk/pull/24047/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24047&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8352022
  Stats: 41 lines in 2 files changed: 41 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/24047.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24047/head:pull/24047

PR: https://git.openjdk.org/jdk/pull/24047