ALSA: pcm - fix mmap capability check for the snd-dummy driver

The snd-dummy driver (fake_buffer configuration) uses the ops->page
callback for the mmap operations. Allow mmap for this case, too.

Cc: <stable@vger.kernel.org>
Fixes: c4824ae7 ("ALSA: pcm: Fix mmap capability check")
Signed-off-by: NJaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20210730090254.612478-1-perex@perex.czSigned-off-by: NTakashi Iwai <tiwai@suse.de>

sound/core/pcm_native.c

@@ -246,7 +246,7 @@ static bool hw_support_mmap(struct snd_pcm_substream *substream)
 	if (!(substream->runtime->hw.info & SNDRV_PCM_INFO_MMAP))
 		return false;
 
-	if (substream->ops->mmap)
+	if (substream->ops->mmap || substream->ops->page)
 		return true;
 
 	switch (substream->dma_buffer.dev.type) {