selftests/livepatch: Disable the timeout

Commit 852c8cbf34d3 ("selftests/kselftest/runner.sh: Add 45 second
timeout per test") introduced a timeout per test. Livepatch tests could
run longer than 45 seconds, especially on slower machines. They do not
hang and they detect if something goes awry with internal accounting.

Better than looking for an arbitrary value, just disable the timeout for
livepatch selftests.

Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>