ALSA: pcm - Call pgprot_noncached() for vmalloc'ed buffers

pgprot_noncached() can be set for vmalloc'ed buffers safely, and we'd
need non-cached behavior more or less, even for the intermediate ring-
buffers.

Now snd_pcm_lib_mmap_vmalloc() is added as the common PCM mmap callback
that is coupled with snd_pcm_lib_alloc_vmalloc_buffer() & co.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/drivers/vx/vx_pcm.c

@@ -905,6 +905,7 @@ static struct snd_pcm_ops vx_pcm_playback_ops = {
 	.trigger =	vx_pcm_trigger,
 	.pointer =	vx_pcm_playback_pointer,
 	.page =		snd_pcm_lib_get_vmalloc_page,
+	.mmap =		snd_pcm_lib_mmap_vmalloc,
 };
 
 
@@ -1125,6 +1126,7 @@ static struct snd_pcm_ops vx_pcm_capture_ops = {
 	.trigger =	vx_pcm_trigger,
 	.pointer =	vx_pcm_capture_pointer,
 	.page =		snd_pcm_lib_get_vmalloc_page,
+	.mmap =		snd_pcm_lib_mmap_vmalloc,
 };