ASoC: wm9713: correct mono out PGA sources

The mono output PGA input only has four possible sources, so
omit the rest.
Signed-off-by: Matt Reimer <mreimer@sdgsystems.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/codecs/wm9713.c

@@ -74,8 +74,7 @@ static const char *wm9713_rec_src[] =
 	"Mono Out", "Zh"};
 static const char *wm9713_rec_gain[] = {"+1.5dB Steps", "+0.75dB Steps"};
 static const char *wm9713_alc_select[] = {"None", "Left", "Right", "Stereo"};
-static const char *wm9713_mono_pga[] = {"Vmid", "Zh", "Mono", "Inv",
-	"Mono Vmid", "Inv Vmid"};
+static const char *wm9713_mono_pga[] = {"Vmid", "Zh", "Mono", "Inv"};
 static const char *wm9713_spk_pga[] =
 	{"Vmid", "Zh", "Headphone", "Speaker", "Inv", "Headphone Vmid",
 	"Speaker Vmid", "Inv Vmid"};