powerpc/perf: Add missing of_node_put()s in imc-pmu.c

In update_events_in_group(), of_find_node_by_phandle() will return
a node pointer with refcount incremented. The reference should be
dropped with of_node_put() in the failure path or when it is not used
anymore.
Signed-off-by: Liang He <windhl@126.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/20220618071353.4059000-1-windhl@126.com

arch/powerpc/perf/imc-pmu.c

@@ -240,8 +240,10 @@ static int update_events_in_group(struct device_node *node, struct imc_pmu *pmu)
 	ct = of_get_child_count(pmu_events);
 
 	/* Get the event prefix */
-	if (of_property_read_string(node, "events-prefix", &prefix))
+	if (of_property_read_string(node, "events-prefix", &prefix)) {
+		of_node_put(pmu_events);
 		return 0;
+	}
 
 	/* Get a global unit and scale data if available */
 	if (of_property_read_string(node, "scale", &g_scale))
@@ -255,8 +257,10 @@ static int update_events_in_group(struct device_node *node, struct imc_pmu *pmu)
 
 	/* Allocate memory for the events */
 	pmu->events = kcalloc(ct, sizeof(struct imc_events), GFP_KERNEL);
-	if (!pmu->events)
+	if (!pmu->events) {
+		of_node_put(pmu_events);
 		return -ENOMEM;
+	}
 
 	ct = 0;
 	/* Parse the events and update the struct */
@@ -266,6 +270,8 @@ static int update_events_in_group(struct device_node *node, struct imc_pmu *pmu)
 			ct++;
 	}
 
+	of_node_put(pmu_events);
+
 	/* Allocate memory for attribute group */
 	attr_group = kzalloc(sizeof(*attr_group), GFP_KERNEL);
 	if (!attr_group) {