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/qfw_cpu.c b/arch/x86/cpu/qfw_cpu.c
index a169783..a35de87 100644
--- a/arch/x86/cpu/qfw_cpu.c
+++ b/arch/x86/cpu/qfw_cpu.c
@@ -18,7 +18,7 @@
 	int cpu_num;
 	int cpu_online;
 	struct udevice *dev, *pdev;
-	struct cpu_platdata *plat;
+	struct cpu_plat *plat;
 	char *cpu;
 
 	/* first we need to find '/cpus' */