livepatch/arm64: support livepatch emit plt call

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

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The livepatch without ftrace mode uses the direct jump method to
implement the livepatch. When KASLR is enabled, the address of the
symbol which need relocate in the module may exceeds the range of
short jump. In the module, this is implemented by the PLT sections.

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.

The .klp.rela.objname.secname section store all symbols that required
relocate by livepatch. For commit 425595a7 ("livepatch: reuse
module loader code to write relocations") merged, load_module can
create enough plt entries for livepatch by module_frob_arch_sections.
we will fix it soon.

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>