[ALSA] sun-cs4231: use cs4231-regs.h

This patch replaces cs4231 registers definitions with
common include.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>