ALSA: dummy: Convert to generic PCM copy ops

This patch converts the dummy driver code to use the new unified PCM
copy callback.  As dummy driver doesn't do anything in the callback,
it's just a simple replacement.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230815190136.8987-5-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/drivers/dummy.c

@@ -626,14 +626,7 @@ static int alloc_fake_buffer(void)
 
 static int dummy_pcm_copy(struct snd_pcm_substream *substream,
 			  int channel, unsigned long pos,
-			  void __user *dst, unsigned long bytes)
-{
-	return 0; /* do nothing */
-}
-
-static int dummy_pcm_copy_kernel(struct snd_pcm_substream *substream,
-				 int channel, unsigned long pos,
-				 void *dst, unsigned long bytes)
+			  struct iov_iter *iter, unsigned long bytes)
 {
 	return 0; /* do nothing */
 }
@@ -667,8 +660,7 @@ static const struct snd_pcm_ops dummy_pcm_ops_no_buf = {
 	.prepare =	dummy_pcm_prepare,
 	.trigger =	dummy_pcm_trigger,
 	.pointer =	dummy_pcm_pointer,
-	.copy_user =	dummy_pcm_copy,
-	.copy_kernel =	dummy_pcm_copy_kernel,
+	.copy =		dummy_pcm_copy,
 	.fill_silence =	dummy_pcm_silence,
 	.page =		dummy_pcm_page,
 };