ALSA: pcm_dmaengine: Add missing module description

Now that make W=1 starts complaining the lack of MODULE_DESCRIPTION(),
let's add the missing information.

Reported-by: Andy Shevchenko <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Signed-off-by: Takashi Iwai <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Reviewed-by: Dragan Simic <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: tiwai

sound/core/pcm_dmaengine.c

@@ -470,4 +470,5 @@ int snd_dmaengine_pcm_refine_runtime_hwparams(
 }
 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_refine_runtime_hwparams);
 
+MODULE_DESCRIPTION("PCM dmaengine helper APIs");
 MODULE_LICENSE("GPL");