KUnit: add missing MODULE_DESCRIPTION() macros for lib/*_test.ko

make allmodconfig && make W=1 C=1 reports for lib/*_test.ko:
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/atomic64_test.o
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/hashtable_test.o

Add the missing invocations of the MODULE_DESCRIPTION() macro.

Link: https://lkml.kernel.org/r/20240601-md-lib-test2-v1-1-be764b785f17@quicinc.comSigned-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/atomic64_test.c

@@ -273,4 +273,5 @@ static __exit void test_atomics_exit(void) {}
 module_init(test_atomics_init);
 module_exit(test_atomics_exit);
 
+MODULE_DESCRIPTION("Testsuite for atomic64_t functions");
 MODULE_LICENSE("GPL");

lib/hashtable_test.c

@@ -314,4 +314,5 @@ static struct kunit_suite hashtable_test_module = {
 
 kunit_test_suites(&hashtable_test_module);
 
+MODULE_DESCRIPTION("KUnit test for the Kernel Hashtable structures");
 MODULE_LICENSE("GPL");