KVM: PPC: Book3S PR: Fix -Werror=return-type build failure

Fixes: 3a167bea ("kvm: powerpc: Add kvmppc_ops callback")
Signed-off-by: David Michael <fedora.dm0@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/kvm/book3s_pr.c

@@ -2030,6 +2030,7 @@ static int kvm_vm_ioctl_get_smmu_info_pr(struct kvm *kvm,
 {
 	/* We should not get called */
 	BUG();
+	return 0;
 }
 #endif /* CONFIG_PPC64 */