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/usb/host/dwc3-of-simple.c b/drivers/usb/host/dwc3-of-simple.c
index 6240a45..9b1edcd 100644
--- a/drivers/usb/host/dwc3-of-simple.c
+++ b/drivers/usb/host/dwc3-of-simple.c
@@ -102,6 +102,6 @@
 	.of_match = dwc3_of_simple_ids,
 	.probe = dwc3_of_simple_probe,
 	.remove = dwc3_of_simple_remove,
-	.platdata_auto	= sizeof(struct dwc3_of_simple),
+	.plat_auto	= sizeof(struct dwc3_of_simple),
 	.flags = DM_FLAG_ALLOC_PRIV_DMA,
 };