KVM: PPC: e500: Fix some NULL dereferences on error

There are some error paths in kvmppc_core_vcpu_create_e500() where we
forget to set the error code.  It means that we return ERR_PTR(0) which
is NULL and it results in a NULL pointer dereference in the caller.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/kvm/e500.c

@@ -455,16 +455,20 @@ static struct kvm_vcpu *kvmppc_core_vcpu_create_e500(struct kvm *kvm,
 	if (err)
 		goto free_vcpu;
 
-	if (kvmppc_e500_id_table_alloc(vcpu_e500) == NULL)
+	if (kvmppc_e500_id_table_alloc(vcpu_e500) == NULL) {
+		err = -ENOMEM;
 		goto uninit_vcpu;
+	}
 
 	err = kvmppc_e500_tlb_init(vcpu_e500);
 	if (err)
 		goto uninit_id;
 
 	vcpu->arch.shared = (void*)__get_free_page(GFP_KERNEL|__GFP_ZERO);
-	if (!vcpu->arch.shared)
+	if (!vcpu->arch.shared) {
+		err = -ENOMEM;
 		goto uninit_tlb;
+	}
 
 	return vcpu;