perf sched: Fix memory leaks for evsel->priv in timehist

perf sched: Fix memory leaks for evsel->priv in timehist

It uses evsel->priv to save per-cpu timing information.  It should be
freed when the evsel is released.

Add the priv destructor for evsel same as thread to handle that.

Fixes: 49394a2a24c78ce0 ("perf sched timehist: Introduce timehist command")
Reviewed-by: Ian Rogers <irogers@google.com>
Tested-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250703014942.1369397-6-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>