list: test: add the missing MODULE_DESCRIPTION() macro

make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/list-test.o

Add the missing invocation of the MODULE_DESCRIPTION() macro.
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

lib/list-test.c

@@ -1493,4 +1493,5 @@ static struct kunit_suite klist_test_module = {
 
 kunit_test_suites(&list_test_module, &hlist_test_module, &klist_test_module);
 
+MODULE_DESCRIPTION("KUnit test for the Kernel Linked-list structures");
 MODULE_LICENSE("GPL v2");