[ALSA] ad1848_lib: replace common delay loop by function

This patch replaces a common delay loop by a function.
It also uses ARRAY_SIZE macro for the rates table.
Acked-by: Rene Herman <rene.herman@gmail.com>
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>