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/net/ethoc.c b/drivers/net/ethoc.c
index cb232f6..640db11 100644
--- a/drivers/net/ethoc.c
+++ b/drivers/net/ethoc.c
@@ -751,7 +751,7 @@
 	.remove				= ethoc_remove,
 	.ops				= &ethoc_ops,
 	.priv_auto		= sizeof(struct ethoc),
-	.platdata_auto	= sizeof(struct ethoc_eth_pdata),
+	.plat_auto	= sizeof(struct ethoc_eth_pdata),
 };
 
 #else