drm/xe/pmu: Get/put runtime pm on event init

When the event is created, make sure runtime pm is taken and later put:
in order to read an event counter the GPU needs to remain accessible and
doing a get/put during perf's read is not possible it's holding a
raw_spinlock.

Suggested-by: Rodrigo Vivi <[e-mail]>
Reviewed-by: Rodrigo Vivi <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Signed-off-by: Lucas De Marchi <[e-mail]>

drivers/gpu/drm/xe/xe_pmu.c

···
 #include <linux/device.h>
 
 #include "xe_device.h"
+#include "xe_pm.h"
 #include "xe_pmu.h"
 
 /**
···
 	struct xe_device *xe = container_of(event->pmu, typeof(*xe), pmu.base);
 
 	drm_WARN_ON(&xe->drm, event->parent);
+	xe_pm_runtime_put(xe);
 	drm_dev_put(&xe->drm);
 }
 
···
 
 	if (!event->parent) {
 		drm_dev_get(&xe->drm);
+		xe_pm_runtime_get(xe);
 		event->destroy = xe_pmu_event_destroy;
 	}