KVM: Unregister cpufreq notifier on unload

Properly unregister cpufreq notifier on onload if it was registered
during init.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/x86.c

@@ -2775,6 +2775,9 @@ out:
 
 void kvm_arch_exit(void)
 {
+	if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
+		cpufreq_unregister_notifier(&kvmclock_cpufreq_notifier_block,
+					    CPUFREQ_TRANSITION_NOTIFIER);
 	kvm_x86_ops = NULL;
 	kvm_mmu_module_exit();
 }