RISC-V: KVM: Allow Svvptc extension for Guest/VM

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

Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/133509ffe5783b62cf95e8f675cc3e327bee402e.1732854096.git.zhouquan@iscas.ac.cn
Signed-off-by: Anup Patel <anup@brainfault.org>

arch/riscv/include/uapi/asm/kvm.h

@@ -179,6 +179,7 @@ enum KVM_RISCV_ISA_EXT_ID {
 	KVM_RISCV_ISA_EXT_SSNPM,
 	KVM_RISCV_ISA_EXT_SVADE,
 	KVM_RISCV_ISA_EXT_SVADU,
+	KVM_RISCV_ISA_EXT_SVVPTC,
 	KVM_RISCV_ISA_EXT_MAX,
 };