RISC-V: KVM: add vector registers and CSRs in KVM_GET_REG_LIST

Add all vector registers and CSRs (vstart, vl, vtype, vcsr, vlenb) in
get-reg-list.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Anup Patel <anup@brainfault.org>