ASoC: soc-dapm: Use empty struct initializer

{ NULL } only clears the first member of the structure.

Even though the first member of the snd_soc_dapm_update struct is a
pointer,it is more robust to use the empty struct initializer that
clears all the struct members.
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-dapm.c

@@ -3165,7 +3165,7 @@ int snd_soc_dapm_put_volsw(struct snd_kcontrol *kcontrol,
 	unsigned int invert = mc->invert;
 	unsigned int val, rval = 0;
 	int connect, rconnect = -1, change, reg_change = 0;
-	struct snd_soc_dapm_update update = { NULL };
+	struct snd_soc_dapm_update update = {};
 	int ret = 0;
 
 	val = (ucontrol->value.integer.value[0] & mask);
@@ -3292,7 +3292,7 @@ int snd_soc_dapm_put_enum_double(struct snd_kcontrol *kcontrol,
 	unsigned int *item = ucontrol->value.enumerated.item;
 	unsigned int val, change, reg_change = 0;
 	unsigned int mask;
-	struct snd_soc_dapm_update update = { NULL };
+	struct snd_soc_dapm_update update = {};
 	int ret = 0;
 
 	if (item[0] >= e->items)