usb: xhci: exynos: variable node should be signed

The variable node is assigned to the return value of a function that
returns an int. It is tested for being negative and then passed as an
argument to a function that takes an int. So 'node' should not be
declared as unsigned. Correct it.

This issue was found by Smatch.

Signed-off-by: Andrew Goodbody <andrew.goodbody@linaro.org>

drivers/usb/host/xhci-exynos5.c

@@ -56,8 +56,7 @@ static int xhci_usb_of_to_plat(struct udevice *dev)
 {
 	struct exynos_xhci_plat *plat = dev_get_plat(dev);
 	const void *blob = gd->fdt_blob;
-	unsigned int node;
-	int depth;
+	int node, depth;
 
 	/*
 	 * Get the base address for XHCI controller from the device node