ASoC: Support !REGULATOR build for sgtl5000

The regulator is optional depending on board design.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c
index 1f7217f..ff29380 100644
--- a/sound/soc/codecs/sgtl5000.c
+++ b/sound/soc/codecs/sgtl5000.c
@@ -772,6 +772,7 @@
 	return 0;
 }
 
+#ifdef CONFIG_REGULATOR
 static int ldo_regulator_is_enabled(struct regulator_dev *dev)
 {
 	struct ldo_regulator *ldo = rdev_get_drvdata(dev);
@@ -901,6 +902,19 @@
 
 	return 0;
 }
+#else
+static int ldo_regulator_register(struct snd_soc_codec *codec,
+				struct regulator_init_data *init_data,
+				int voltage)
+{
+	return -EINVAL;
+}
+
+static int ldo_regulator_remove(struct snd_soc_codec *codec)
+{
+	return 0;
+}
+#endif
 
 /*
  * set dac bias