[ALSA] cs4231-lib: improved waiting after mce_down

This patch replaces long msleeps in waiting loops
with schedule_timeout() calls.

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