dm: treewide: Rename 'platdata' variables to just 'plat'

We use 'priv' for private data but often use 'platdata' for platform data.
We can't really use 'pdata' since that is ambiguous (it could mean private
or platform data).

Rename some of the latter variables to end with 'plat' for consistency.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/gpio/mpc83xx_spisel_boot.c b/drivers/gpio/mpc83xx_spisel_boot.c
index 3020cc95..dae94b5 100644
--- a/drivers/gpio/mpc83xx_spisel_boot.c
+++ b/drivers/gpio/mpc83xx_spisel_boot.c
@@ -141,7 +141,7 @@
 	.ops	= &mpc83xx_spisel_boot_ops,
 #if CONFIG_IS_ENABLED(OF_CONTROL)
 	.ofdata_to_platdata = mpc83xx_spisel_boot_ofdata_to_platdata,
-	.platdata_auto	= sizeof(struct mpc8xxx_gpio_plat),
+	.plat_auto	= sizeof(struct mpc8xxx_gpio_plat),
 	.of_match = mpc83xx_spisel_boot_ids,
 #endif
 	.probe	= mpc83xx_spisel_boot_probe,