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/misc/imx8/scu.c b/drivers/misc/imx8/scu.c
index 5a2a0e6..65e34d5 100644
--- a/drivers/misc/imx8/scu.c
+++ b/drivers/misc/imx8/scu.c
@@ -245,6 +245,6 @@
 	.bind		= imx8_scu_bind,
 	.remove		= imx8_scu_remove,
 	.ops		= &imx8_scu_ops,
-	.platdata_auto	= sizeof(struct imx8_scu),
+	.plat_auto	= sizeof(struct imx8_scu),
 	.flags		= DM_FLAG_PRE_RELOC,
 };