'klist_test_struct' has been unused since the original
commit 57b4f760 ("list: test: Test the klist structure").

Remove it.
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>