riscv: KVM: allow Zilsd and Zclsd extensions for Guest/VM

riscv: KVM: allow Zilsd and Zclsd extensions for Guest/VM

Extend the KVM ISA extension ONE_REG interface to allow KVM user space
to detect and enable Zilsd and Zclsd extensions for Guest/VM.

Signed-off-by: Pincheng Wang <pincheng.plct@isrc.iscas.ac.cn>
Reviewed-by: Nutty Liu <nutty.liu@hotmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20250826162939.1494021-5-pincheng.plct@isrc.iscas.ac.cn
Signed-off-by: Anup Patel <anup@brainfault.org>