KVM: x86: Fix uninitialized return code

This is a regression caused by 18595411.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

arch/x86/kvm/x86.c

@@ -3006,6 +3006,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 		break;
 	}
 	case KVM_SET_LAPIC: {
+		r = -EINVAL;
 		if (!vcpu->arch.apic)
 			goto out;
 		u.lapic = memdup_user(argp, sizeof(*u.lapic));