ASoC: ad1980: Remove unused header

The constants defined in the ad1980 header are not used. So remove the file.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/ad1980.c

@@ -30,8 +30,6 @@
 #include <sound/initval.h>
 #include <sound/soc.h>
 
-#include "ad1980.h"
-
 /*
  * AD1980 register cache
  */