dm: treewide: Rename ..._platdata variables to just ..._plat

Try to maintain some consistency between these variables by using _plat as
a suffix for them.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/cpu/cpu-uclass.c b/drivers/cpu/cpu-uclass.c
index 55cb172..1c338ba 100644
--- a/drivers/cpu/cpu-uclass.c
+++ b/drivers/cpu/cpu-uclass.c
@@ -115,7 +115,7 @@
 U_BOOT_DRIVER(cpu_bus) = {
 	.name	= "cpu_bus",
 	.id	= UCLASS_SIMPLE_BUS,
-	.per_child_plat_auto	= sizeof(struct cpu_platdata),
+	.per_child_plat_auto	= sizeof(struct cpu_plat),
 };
 
 static int uclass_cpu_init(struct uclass *uc)