[ALSA] Fix typo and add entry to documentation

This patch adds the macpro and fixes a typo in the ALC882 section of
ALSA-Configuration.txt.

Signed-off-by: Tobin Davis <tdavis@dsl-only.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

Documentation/sound/alsa/ALSA-Configuration.txt

@@ -814,8 +814,9 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
 
 	ALC882/885
 	  3stack-dig	3-jack with SPDIF I/O
-	  6stck-dig	6-jack digital with SPDIF I/O
+	  6stack-dig	6-jack digital with SPDIF I/O
 	  arima		Arima W820Di1
+	  macpro	MacPro support
 	  auto		auto-config reading BIOS (default)
 
 	ALC883/888