selftests: livepatch: Add initial .gitignore

Ignore the binary used to test livepatching a syscall.
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/livepatch/.gitignore

+test_klp-call_getpid