ARM: imx: Assign parents for mmdc event_source devices

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/
Cc: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/mach-imx/mmdc.c

@@ -437,6 +437,7 @@ static int mmdc_pmu_init(struct mmdc_pmu *pmu_mmdc,
 {
 	*pmu_mmdc = (struct mmdc_pmu) {
 		.pmu = (struct pmu) {
+			.parent		= dev,
 			.task_ctx_nr    = perf_invalid_context,
 			.attr_groups    = attr_groups,
 			.event_init     = mmdc_pmu_event_init,