selftests/livepatch: fix selftest execution error

kylin inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IB7CZ5



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The selftest scripts fails with the following error:
$ sudo ./test-callbacks.sh
TEST: target module before livepatch ... not ok
$ sudo ./test-ftrace.sh
TEST: livepatch interaction with ftrace_enabled sysctl ... not ok
$ sudo ./test-livepatch.sh
TEST: basic function patching ... not ok
$ sudo ./test-state.sh
TEST: system state modification ... not ok
$ sudo ./test-syscall.sh
TEST: patch getpid syscall while being heavily hammered ... not ok
$ sudo ./test-sysfs.sh
TEST: sysfs test ... not ok

Fixes: 601dd19c ("livepatch/core: Reuse common codes in the solution without ftrace")

Signed-off-by: George Guo <guodongtai@kylinos.cn>