ASoC: topology: Fix a potential NULL pointer dereference in 'soc_tplg_dapm_widget_denum_create()'

if 'se = kzalloc()' fails in the 'for' loop, we will branch to 'err'.
But in this case, 'kc[i].private_value' will still be NULL. A NULL pointer
dereference will then occur is the error handling path.

In such a case, it is safe to just 'continue' in order to skip this entry
and free the other ones.

Fixes: 1a7dd6e2f1 ("ASoC: topology: Allow a widget to have multiple enum controls")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-topology.c

@@ -1378,6 +1378,9 @@ err_se:
 	for (; i >= 0; i--) {
 		/* free values and texts */
 		se = (struct soc_enum *)kc[i].private_value;
+		if (!se)
+			continue;
+
 		kfree(se->dobj.control.dvalues);
 		for (j = 0; j < ec->items; j++)
 			kfree(se->dobj.control.dtexts[j]);