powerpc/perf: Fix double unlock in imc_common_cpuhp_mem_free()

This function is not called with the nest_init_lock held, and it also
unlocks the nest_init_lock immediately below, so it's fairly clear
that this is a typo and should be locking the lock.

Fixes: 885dcd709ba9 ("powerpc/perf: Add nest IMC PMU support")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/perf/imc-pmu.c

@@ -1124,7 +1124,7 @@ static void cleanup_all_thread_imc_memory(void)
 static void imc_common_cpuhp_mem_free(struct imc_pmu *pmu_ptr)
 {
 	if (pmu_ptr->domain == IMC_DOMAIN_NEST) {
-		mutex_unlock(&nest_init_lock);
+		mutex_lock(&nest_init_lock);
 		if (nest_pmus == 1) {
 			cpuhp_remove_state(CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE);
 			kfree(nest_imc_refc);