perf header: Fix one memory leakage in perf_event__fprintf_event_update()

driver inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8MEWF


CVE: NA

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When dump the raw trace by `perf report -D` ASan reports a memory
leakage in perf_event__fprintf_event_update(). It shows that we
allocated a temporary cpumap for dumping the CPUs but doesn't
release it and it's not used elsewhere. Fix this by free the
cpumap after the dumping.

Fixes: c853f939 ("perf tools: Add perf_event__fprintf_event_update function")
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Junhao He <hejunhao3@huawei.com>