interconnect: imx: Remove a useless test

'dn' can't be NULL here, it is tested just the line above.
Remove this useless test.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/20201206121322.29434-1-christophe.jaillet@wanadoo.frSigned-off-by: Georgi Djakov <georgi.djakov@linaro.org>

drivers/interconnect/imx/imx.c

@@ -96,7 +96,7 @@ static int imx_icc_node_init_qos(struct icc_provider *provider,
 			return -ENODEV;
 		}
 		/* Allow scaling to be disabled on a per-node basis */
-		if (!dn || !of_device_is_available(dn)) {
+		if (!of_device_is_available(dn)) {
 			dev_warn(dev, "Missing property %s, skip scaling %s\n",
 				 adj->phandle_name, node->name);
 			of_node_put(dn);