x86/perf: fix use-after-free bug in uncore_pci_remove()

zhaoxin inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7066J


CVE: NA

Reference: N/A

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since the dereferencing freed memory 'box' in uncore_pci_remove() will
trigger a use-after-free bug, use a variable 'name' to store the value of
box->pmu->type->name, so that the memory 'box' won't be dereferenced after
being released.

Signed-off-by: Ziqin Liu <ziqin_l@hust.edu.cn>