powerpc/pci: fix warning comparing pointer to 0

Fix the following coccicheck warning:

./arch/powerpc/platforms/maple/pci.c:37:16-17: WARNING comparing pointer
to 0.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1615793724-97015-1-git-send-email-jiapeng.chong@linux.alibaba.com

arch/powerpc/platforms/maple/pci.c

@@ -34,7 +34,7 @@ static struct pci_controller *u3_agp, *u3_ht, *u4_pcie;
 
 static int __init fixup_one_level_bus_range(struct device_node *node, int higher)
 {
-	for (; node != 0;node = node->sibling) {
+	for (; node; node = node->sibling) {
 		const int *bus_range;
 		const unsigned int *class_code;
 		int len;