[ALSA] ad1848: Fix msleep while atomic

Simplest fix.
Acked-by: Rene Herman <rene.herman@gmail.com>

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>