powerpc/pasemi: Use of_root in pas_pci_init()

Currently in pas_pci_init() a reference to the root node is leaked due
to a missing of_node_put(). Instead just use of_root directly.

Note that converting to of_find_compatible_node(NULL, ...) would
not be entirely equivalent, because that would check the compatible
property of the root node, whereas using of_root skips checking the root
node and start the search at the first child of the root.
Reported-by: Liang He <windhl@126.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220906010313.1296714-1-mpe@ellerman.id.au

arch/powerpc/platforms/pasemi/pci.c

@@ -270,18 +270,12 @@ static int __init pas_add_bridge(struct device_node *dev)
 
 void __init pas_pci_init(void)
 {
-	struct device_node *np, *root;
+	struct device_node *np;
 	int res;
 
-	root = of_find_node_by_path("/");
-	if (!root) {
-		pr_crit("pas_pci_init: can't find root of device tree\n");
-		return;
-	}
-
 	pci_set_flags(PCI_SCAN_ALL_PCIE_DEVS);
 
-	np = of_find_compatible_node(root, NULL, "pasemi,rootbus");
+	np = of_find_compatible_node(of_root, NULL, "pasemi,rootbus");
 	if (np) {
 		res = pas_add_bridge(np);
 		of_node_put(np);