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/gpio/hi6220_gpio.c b/drivers/gpio/hi6220_gpio.c
index 02a3782..f5e5fc6 100644
--- a/drivers/gpio/hi6220_gpio.c
+++ b/drivers/gpio/hi6220_gpio.c
@@ -66,7 +66,7 @@
 static int hi6220_gpio_probe(struct udevice *dev)
 {
 	struct gpio_bank *bank = dev_get_priv(dev);
-	struct hikey_gpio_platdata *plat = dev_get_plat(dev);
+	struct hikey_gpio_plat *plat = dev_get_plat(dev);
 	struct gpio_dev_priv *uc_priv = dev->uclass_priv;
 	char name[18], *str;