asoc: codecs: Add default case for switch.

Add default case for switch to avoid the
Null pointer dereference for the map and num_ports
variable in for loop.

Change-Id: I59c9dc6e5396bcb409876378c811143da1c81551
Signed-off-by: Prasad Kumpatla <nkumpat@codeaurora.org>
diff --git a/asoc/codecs/wcd937x/wcd937x.c b/asoc/codecs/wcd937x/wcd937x.c
index 30ad7e3..d5315c8 100644
--- a/asoc/codecs/wcd937x/wcd937x.c
+++ b/asoc/codecs/wcd937x/wcd937x.c
@@ -163,6 +163,10 @@
 		map = &wcd937x->tx_port_mapping;
 		num_ports = wcd937x->num_tx_ports;
 		break;
+	default:
+		dev_err(component->dev, "%s Invalid path selected %u\n",
+					__func__, path);
+		return -EINVAL;
 	}
 
 	for (i = 0; i <= num_ports; i++) {
@@ -207,6 +211,10 @@
 		map = &wcd937x->tx_port_mapping;
 		num_ports = &wcd937x->num_tx_ports;
 		break;
+	default:
+		dev_err(dev, "%s Invalid path selected %u\n",
+				 __func__, path);
+		return -EINVAL;
 	}
 
 	if (!of_find_property(dev->of_node, prop,