ALSA: kunit: Add missing module descriptions

Now that make W=1 starts complaining the lack of MODULE_DESCRIPTION(),
let's add the missing information.
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Closes: https://lore.kernel.org/r/ZjpQm-hxLQtpgkUx@smile.fi.intel.comSigned-off-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Dragan Simic <dsimic@manjaro.org>
Link: https://lore.kernel.org/r/20240508091128.25274-5-tiwai@suse.de

sound/core/sound_kunit.c

@@ -308,5 +308,6 @@ static struct kunit_suite sound_utils_suite = {
 };
 
 kunit_test_suite(sound_utils_suite);
+MODULE_DESCRIPTION("Sound core KUnit test");
 MODULE_AUTHOR("Ivan Orlov");
 MODULE_LICENSE("GPL");