drm/i915/pmu: Remove pointless synchronize_rcu() call

This is already done inside perf_pmu_unregister() - no need to do it
before.

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241104213512.2314930-5-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

Author: Lucas De Marchi

drivers/gpu/drm/i915/i915_pmu.c

@@ -1335,13 +1335,8 @@ void i915_pmu_unregister(struct drm_i915_private *i915)
 	if (!pmu->registered)
 		return;
 
-	/*
-	 * "Disconnect" the PMU callbacks - since all are atomic synchronize_rcu
-	 * ensures all currently executing ones will have exited before we
-	 * proceed with unregistration.
-	 */
+	/* Disconnect the PMU callbacks */
 	pmu->registered = false;
-	synchronize_rcu();
 
 	hrtimer_cancel(&pmu->timer);