KVM: PPC: Remove unused kvm_unmap_hva callback

Since commit fb1522e099 ("KVM: update to new mmu_notifier semantic
v2", 2017-08-31), the MMU notifier code in KVM no longer calls the
kvm_unmap_hva callback.  This removes the PPC implementations of
kvm_unmap_hva().

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/kvm/e500_mmu_host.c

@@ -724,7 +724,7 @@ int kvmppc_load_last_inst(struct kvm_vcpu *vcpu, enum instruction_type type,
 
 /************* MMU Notifiers *************/
 
-int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
+static int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
 {
 	trace_kvm_unmap_hva(hva);