ASoC: twl6040 - add method to query HS DC offset step size in mV

Provide a method for mach drivers to query the HS DC offset step size in mV.

Signed-off-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/codecs/twl6040.h b/sound/soc/codecs/twl6040.h
index ef273f1..0611406 100644
--- a/sound/soc/codecs/twl6040.h
+++ b/sound/soc/codecs/twl6040.h
@@ -39,5 +39,6 @@
 			    struct snd_soc_jack *jack, int report);
 int twl6040_get_clk_id(struct snd_soc_codec *codec);
 int twl6040_get_trim_value(struct snd_soc_codec *codec, enum twl6040_trim trim);
+int twl6040_get_hs_step_size(struct snd_soc_codec *codec);
 
 #endif /* End of __TWL6040_H__ */