[ALSA] ad1848: Fix msleep while atomic

Simplest fix.
Acked-by: NRene Herman <rene.herman@gmail.com>
Signed-off-by: NTrent Piepho <xyzzy@speakeasy.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NJaroslav Kysela <perex@suse.cz>

sound/isa/ad1848/ad1848_lib.c

@@ -236,7 +236,9 @@ static void snd_ad1848_mce_down(struct snd_ad1848 *chip)
 	 * calibration process to start. Needs upto 5 sample periods on AD1848
 	 * which at the slowest possible rate of 5.5125 kHz means 907 us.
 	 */
+	spin_unlock_irqrestore(&chip->reg_lock, flags);
 	msleep(1);
+	spin_lock_irqsave(&chip->reg_lock, flags);
 
 	snd_printdd("(2) jiffies = %lu\n", jiffies);