net: mvneta: Fix unused variable warning if DM_GPIO is disabled

The `ret` variable in mvneta_probe() is unused if DM_GPIO is disabled.

Since the variable is used only once after assigning value, we can
inline the usage and drop the variable.

Signed-off-by: Marek BehĂșn <marek.behun@nic.cz>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/drivers/net/mvneta.c b/drivers/net/mvneta.c
index 19f8145..72789fc 100644
--- a/drivers/net/mvneta.c
+++ b/drivers/net/mvneta.c
@@ -1570,7 +1570,6 @@
 	int node = dev_of_offset(dev);
 	void *bd_space;
 	int fl_node;
-	int ret;
 
 	/*
 	 * Allocate buffer area for descs and rx_buffers. This is only
@@ -1617,8 +1616,8 @@
 	}
 
 #if CONFIG_IS_ENABLED(DM_GPIO)
-	ret = dev_read_phandle_with_args(dev, "sfp", NULL, 0, 0, &sfp_args);
-	if (!ret && ofnode_is_enabled(sfp_args.node))
+	if (!dev_read_phandle_with_args(dev, "sfp", NULL, 0, 0, &sfp_args) &&
+	    ofnode_is_enabled(sfp_args.node))
 		gpio_request_by_name_nodev(sfp_args.node, "tx-disable-gpio", 0,
 					   &pp->sfp_tx_disable_gpio, GPIOD_IS_OUT);