livepatch/arm64: delete unuse livepatch.pltcount

euler inclusion
category: feature
Bugzilla: 5507
CVE: N/A

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In previous versions, kpatch-build front-tools create an
section named livepatch.pltcount to store the number of
the relocations in the size field, we append enough space
in .plt section for the long jump plts by module_frob_arch_sections.
Now, This's no longer needed. just delete it.

Signed-off-by: Cheng Jian <cj.chengjian@huawei.com>
Reviewed-by: Li Bin <huawei.libin@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>