RISC-V: KVM: Add vmid field to struct kvm_riscv_hfence

RISC-V: KVM: Add vmid field to struct kvm_riscv_hfence

Currently, the struct kvm_riscv_hfence does not have vmid field
and various hfence processing functions always pick vmid assigned
to the guest/VM. This prevents us from doing hfence operation on
arbitrary vmid hence add vmid field to struct kvm_riscv_hfence
and use it wherever applicable.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Tested-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Nutty Liu <liujingqi@lanxincomputing.com>
Link: https://lore.kernel.org/r/20250618113532.471448-11-apatel@ventanamicro.com
Signed-off-by: Anup Patel <anup@brainfault.org>