ASoC: pcm1681: Fix max_register setting

According to the datasheet, the max_register is 13h.
ARRAY_SIZE(pcm1681_reg_defaults) + 1 is 18 which is wrong.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/sound/soc/codecs/pcm1681.c b/sound/soc/codecs/pcm1681.c
index 651ce09..c91eba5 100644
--- a/sound/soc/codecs/pcm1681.c
+++ b/sound/soc/codecs/pcm1681.c
@@ -270,7 +270,7 @@
 static const struct regmap_config pcm1681_regmap = {
 	.reg_bits		= 8,
 	.val_bits		= 8,
-	.max_register		= ARRAY_SIZE(pcm1681_reg_defaults) + 1,
+	.max_register		= 0x13,
 	.reg_defaults		= pcm1681_reg_defaults,
 	.num_reg_defaults	= ARRAY_SIZE(pcm1681_reg_defaults),
 	.writeable_reg		= pcm1681_writeable_reg,