ASoC: wm_adsp: Use more generic naming for regions and caps definitions

The region definition will be shared by most firmwares so give this a
more generic name and whilst we are there improve the naming of the
voice control capabilities array as well.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>