ASoC: ab8500: Add missing module description

Now that make W=1 starts complaining the lack of MODULE_DESCRIPTION(),
let's add the missing information.
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: 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/20240508091909.27062-2-tiwai@suse.deSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/ab8500-codec.c

@@ -2571,4 +2571,5 @@ static struct platform_driver ab8500_codec_platform_driver = {
 };
 module_platform_driver(ab8500_codec_platform_driver);
 
+MODULE_DESCRIPTION("ASoC AB8500 codec driver");
 MODULE_LICENSE("GPL v2");