perf/arm-ccn: Assign parents for event_source device

Currently the PMU device appears directly under /sys/devices/
Only root busses should appear there, so instead assign the pmu->dev
parent to be the platform device.

Link: https://lore.kernel.org/linux-cxl/ZCLI9A40PJsyqAmq@kroah.com/Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240412161057.14099-20-Jonathan.Cameron@huawei.comSigned-off-by: Will Deacon <will@kernel.org>

drivers/perf/arm-ccn.c

@@ -1265,6 +1265,7 @@ static int arm_ccn_pmu_init(struct arm_ccn *ccn)
 	/* Perf driver registration */
 	ccn->dt.pmu = (struct pmu) {
 		.module = THIS_MODULE,
+		.parent = ccn->dev,
 		.attr_groups = arm_ccn_pmu_attr_groups,
 		.task_ctx_nr = perf_invalid_context,
 		.event_init = arm_ccn_pmu_event_init,