dm: core: Access device ofnode through functions

At present ofnode is present in the device even if it is never used. With
of-platdata this field is not used, so can be removed. In preparation for
this, change the access to go through inline functions.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/misc/swap_case.c b/drivers/misc/swap_case.c
index abea0e7..3cbc8f3 100644
--- a/drivers/misc/swap_case.c
+++ b/drivers/misc/swap_case.c
@@ -54,7 +54,7 @@
 
 static int sandbox_swap_case_use_ea(const struct udevice *dev)
 {
-	return !!ofnode_get_property(dev->node, "use-ea", NULL);
+	return !!ofnode_get_property(dev_ofnode(dev), "use-ea", NULL);
 }
 
 /* Please keep these macros in sync with ea_regs below */