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/sh_eth.c b/drivers/net/sh_eth.c
index a5bd459..b1b8731 100644
--- a/drivers/net/sh_eth.c
+++ b/drivers/net/sh_eth.c
@@ -958,7 +958,7 @@
 	.remove		= sh_ether_remove,
 	.ops		= &sh_ether_ops,
 	.priv_auto	= sizeof(struct sh_ether_priv),
-	.platdata_auto	= sizeof(struct eth_pdata),
+	.plat_auto	= sizeof(struct eth_pdata),
 	.flags		= DM_FLAG_ALLOC_PRIV_DMA,
 };
 #endif