ALSA: memalloc: Support WC allocation on all architectures

There are the generic DMA API calls for allocating and managing the
pages with the write-combined attribute.  Let's use them for all
architectures but x86; x86 still needs the special handling to
override the page attributes.

Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210802072815.13551-5-tiwai@suse.de


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