enable simd on riscv64

Change-Id: I446d6b14e4f89164b49a66367340d904ba104911
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3347493Reviewed-by: ji qiu <qiuji@iscas.ac.cn>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Yahan Lu <yahan@iscas.ac.cn>
Cr-Commit-Position: refs/heads/main@{#78553}