RISC-V: KVM: Use Svinval for local TLB maintenance when available

We should prefer HINVAL.GVMA and HINVAL.VVMA instruction for local TLB
maintenance when underlying host supports Svinval extension.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>