KVM: arm/arm64: enable KVM_CAP_IOEVENTFD

As the infrastructure for eventfd has now been merged, report the
ioeventfd capability as being supported.

Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
[maz: grouped the case entry with the others, fixed commit log]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

arch/arm/kvm/arm.c

@@ -172,6 +172,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	switch (ext) {
 	case KVM_CAP_IRQCHIP:
 	case KVM_CAP_IRQFD:
+	case KVM_CAP_IOEVENTFD:
 	case KVM_CAP_DEVICE_CTRL:
 	case KVM_CAP_USER_MEMORY:
 	case KVM_CAP_SYNC_MMU: