ALSA: intel_hdmi: Use the new non-cached allocation

The HDMI LPE audio driver requires the non-cached page allocations for
its buffers.  With the recent support of SNDRV_DMA_TYPE_DEV_UC type,
we can reduce lots of codes in the driver side and let the memalloc
core doing it properly.

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