RFR: 8323748: RISC-V: Add Zfh probe code

[Fei Yang]

On Fri, 19 Jan 2024 14:28:43 GMT, Hamlin Li <mli at openjdk.org> wrote:

> Hi,
> Can you review this simple patch to add zfh probe code which is a remaining task of [JDK-8318227](https://bugs.openjdk.org/browse/JDK-8318227)?
> Thanks.
> 
> FYI: zfh extension is in the [kernel code](https://github.com/torvalds/linux/blob/master/arch/riscv/include/uapi/asm/hwprobe.h) already.

Looks good. Thanks.

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

Marked as reviewed by fyang (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/17498#pullrequestreview-1834237244