ASoC: wm8974: Use SOC_ENUM_SINGLE_DECL()

Just replace with the helper macro.  No functional change at all.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/codecs/wm8974.c

@@ -84,8 +84,8 @@ static const struct soc_enum wm8974_enum[] = {
 
 static const char *wm8974_auxmode_text[] = { "Buffer", "Mixer" };
 
-static const struct soc_enum wm8974_auxmode =
-	SOC_ENUM_SINGLE(WM8974_INPUT,  3, 2, wm8974_auxmode_text);
+static SOC_ENUM_SINGLE_DECL(wm8974_auxmode,
+			    WM8974_INPUT,  3, wm8974_auxmode_text);
 
 static const DECLARE_TLV_DB_SCALE(digital_tlv, -12750, 50, 1);
 static const DECLARE_TLV_DB_SCALE(eq_tlv, -1200, 100, 0);