powerpc/83xx: Add missing of_node_put() after of_device_is_available()

Add an of_node_put() when a tested device node is not available.

Fixes: c026c987 ("powerpc/83xx: Do not configure or probe disabled FSL DR USB controllers")
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/83xx/usb.c

@@ -221,8 +221,10 @@ int mpc837x_usb_cfg(void)
 	int ret = 0;
 
 	np = of_find_compatible_node(NULL, NULL, "fsl-usb2-dr");
-	if (!np || !of_device_is_available(np))
+	if (!np || !of_device_is_available(np)) {
+		of_node_put(np);
 		return -ENODEV;
+	}
 	prop = of_get_property(np, "phy_type", NULL);
 
 	if (!prop || (strcmp(prop, "ulpi") && strcmp(prop, "serial"))) {