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/arch/x86/cpu/cpu_x86.c b/arch/x86/cpu/cpu_x86.c
index 57441c1..bfb511a 100644
--- a/arch/x86/cpu/cpu_x86.c
+++ b/arch/x86/cpu/cpu_x86.c
@@ -13,7 +13,7 @@
 
 int cpu_x86_bind(struct udevice *dev)
 {
-	struct cpu_platdata *plat = dev_get_parent_plat(dev);
+	struct cpu_plat *plat = dev_get_parent_plat(dev);
 	struct cpuid_result res;
 
 	plat->cpu_id = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev),