kvm: update_memslots: clean flags for invalid memslots

Indeed, any invalid memslots should be new->npages = 0,
new->base_gfn = 0 and new->flags = 0 at the same time.
Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

virt/kvm/kvm_main.c

@@ -675,6 +675,7 @@ static void update_memslots(struct kvm_memslots *slots,
 	if (!new->npages) {
 		WARN_ON(!mslots[i].npages);
 		new->base_gfn = 0;
+		new->flags = 0;
 		if (mslots[i].npages)
 			slots->used_slots--;
 	} else {