Now the ALSA memory allocator helper supports the new non-cached
pages, let's use the new type, SNDRV_DMA_TYPE_DEV_UC_SG, for HD-audio
driver.  This allows us to reduce lots of codes.

As another positive side-effect by this patch, the long-standing issue
with non-snoop mode playing in the non-mmap mode is fixed.  The core
memalloc helper does the proper pgprot setup for non-cached pages for
vmap(), which was missing in the past.
Reported-and-tested-by: Hans Hu <HansHu@zhaoxin.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>