ASoC: dapm: fix snd_soc_dapm_new_control() implicit declaration

The change fixes the following compilation problem:

  sound/soc/soc-dapm.c: In function 'dapm_kcontrol_data_alloc':
  sound/soc/soc-dapm.c:388:4: error: implicit declaration of function
    'snd_soc_dapm_new_control' [-Werror=implicit-function-declaration]
    data->widget = snd_soc_dapm_new_control(widget->dapm,
    ^

  sound/soc/soc-dapm.c:387:17: warning: assignment makes pointer
    from integer without a cast [enabled by default]
    data->widget = snd_soc_dapm_new_control(widget->dapm,
                 ^
  sound/soc/soc-dapm.c: At top level:
  sound/soc/soc-dapm.c:3269:1: error: conflicting types for
    'snd_soc_dapm_new_control'
  snd_soc_dapm_new_control(struct snd_soc_dapm_context *dapm,
  ^

In addition to the fix add static qualifier to
snd_soc_dapm_new_control() function to silence checkpatch.

Fixes: 02aa78abec ("ASoC: DAPM: Add APIs to create individual DAPM controls.")
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-dapm.c

@@ -52,6 +52,11 @@ static int snd_soc_dapm_add_path(struct snd_soc_dapm_context *dapm,
 	const char *control,
 	int (*connected)(struct snd_soc_dapm_widget *source,
 			 struct snd_soc_dapm_widget *sink));
+
+static struct snd_soc_dapm_widget *
+snd_soc_dapm_new_control(struct snd_soc_dapm_context *dapm,
+			 const struct snd_soc_dapm_widget *widget);
+
 struct snd_soc_dapm_widget *
 snd_soc_dapm_new_control_unlocked(struct snd_soc_dapm_context *dapm,
 			 const struct snd_soc_dapm_widget *widget);
@@ -3265,7 +3270,7 @@ int snd_soc_dapm_put_pin_switch(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_GPL(snd_soc_dapm_put_pin_switch);
 
-struct snd_soc_dapm_widget *
+static struct snd_soc_dapm_widget *
 snd_soc_dapm_new_control(struct snd_soc_dapm_context *dapm,
 	const struct snd_soc_dapm_widget *widget)
 {