ALSA: x86: Use standard mmap helper for Intel HDMI LPE audio

Intel HDMI LPE audio driver has its own mmap callback that mimics with
the noncached page attributes, but this is rather superfluous and can
be replaced with the standard helper, as the device is only for
playback and the write-cache should suffice.

This patch drops the own code and just uses the standard helper.

Link: https://lore.kernel.org/r/20220305083308.15718-1-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/x86/intel_hdmi_audio.c

@@ -1253,18 +1253,6 @@ static snd_pcm_uframes_t had_pcm_pointer(struct snd_pcm_substream *substream)
 	return len;
 }
 
-/*
- * ALSA PCM mmap callback
- */
-static int had_pcm_mmap(struct snd_pcm_substream *substream,
-			struct vm_area_struct *vma)
-{
-	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
-	return remap_pfn_range(vma, vma->vm_start,
-			substream->runtime->dma_addr >> PAGE_SHIFT,
-			vma->vm_end - vma->vm_start, vma->vm_page_prot);
-}
-
 /*
  * ALSA PCM ops
  */
@@ -1276,7 +1264,6 @@ static const struct snd_pcm_ops had_pcm_ops = {
 	.trigger =	had_pcm_trigger,
 	.sync_stop =	had_pcm_sync_stop,
 	.pointer =	had_pcm_pointer,
-	.mmap =		had_pcm_mmap,
 };
 
 /* process mode change of the running stream; called in mutex */