ASoC: simple-card: fix possible uninitialized single_cpu local variable

The 'single_cpu' local variable is assigned by asoc_simple_parse_dai()
and later used in a asoc_simple_canonicalize_cpu() call, assuming the
entire function did not exit on errors.

However the first function returns 0 if passed device_node is NULL,
thus leaving the variable uninitialized and reporting success.

Addresses-Coverity: Uninitialized scalar variable
Fixes: 8f7f298a ("ASoC: simple-card-utils: separate asoc_simple_card_parse_dai()")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Sameer Pujar <spujar@nvidia.com>
Link: https://lore.kernel.org/r/20210407092027.60769-1-krzysztof.kozlowski@canonical.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/generic/audio-graph-card.c

@@ -367,7 +367,7 @@ static int graph_dai_link_of(struct asoc_simple_priv *priv,
 	struct device_node *top = dev->of_node;
 	struct asoc_simple_dai *cpu_dai;
 	struct asoc_simple_dai *codec_dai;
-	int ret, single_cpu;
+	int ret, single_cpu = 0;
 
 	dev_dbg(dev, "link_of (%pOF)\n", cpu_ep);
 

sound/soc/generic/simple-card.c

@@ -249,7 +249,7 @@ static int simple_dai_link_of(struct asoc_simple_priv *priv,
 	struct device_node *plat = NULL;
 	char prop[128];
 	char *prefix = "";
-	int ret, single_cpu;
+	int ret, single_cpu = 0;
 
 	cpu  = np;
 	node = of_get_parent(np);