KVM: riscv: selftests: Add bfloat16 extension to get-reg-list test

KVM: riscv: selftests: Add bfloat16 extension to get-reg-list test

The KVM RISC-V allows Zfbfmin/Zvfbfmin/Zvfbfwma extensions for Guest/VM
so add them to get-reg-list test.

Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Nutty Liu <nutty.liu@hotmail.com>
Reviewed-by: Nutty Liu <liujingqi@lanxincomputing.com>
Link: https://lore.kernel.org/r/40e52ff7053401a2fcb206e75f45ebc8557fc28b.1754646071.git.zhouquan@iscas.ac.cn
Signed-off-by: Anup Patel <anup@brainfault.org>