dpaa2-mac: bail if the dpmacs fwnode is not found

The parent pointer node handler must be declared with a NULL
initializer. Before using it, a check must be performed to make
sure that a valid address has been assigned to it.
Signed-off-by: Robert-Ionut Alexa <robert-ionut.alexa@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c

@@ -41,7 +41,7 @@ static int phy_mode(enum dpmac_eth_if eth_if, phy_interface_t *if_mode)
 static struct fwnode_handle *dpaa2_mac_get_node(struct device *dev,
 						u16 dpmac_id)
 {
-	struct fwnode_handle *fwnode, *parent, *child  = NULL;
+	struct fwnode_handle *fwnode, *parent = NULL, *child  = NULL;
 	struct device_node *dpmacs = NULL;
 	int err;
 	u32 id;
@@ -56,6 +56,9 @@ static struct fwnode_handle *dpaa2_mac_get_node(struct device *dev,
 		parent = fwnode;
 	}
 
+	if (!parent)
+		return NULL;
+
 	fwnode_for_each_child_node(parent, child) {
 		err = -EINVAL;
 		if (is_acpi_device_node(child))