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/gmac_rockchip.c b/drivers/net/gmac_rockchip.c
index 1b1e7a8..0bd1da5 100644
--- a/drivers/net/gmac_rockchip.c
+++ b/drivers/net/gmac_rockchip.c
@@ -760,6 +760,6 @@
 	.probe	= gmac_rockchip_probe,
 	.ops	= &gmac_rockchip_eth_ops,
 	.priv_auto	= sizeof(struct dw_eth_dev),
-	.platdata_auto	= sizeof(struct gmac_rockchip_platdata),
+	.plat_auto	= sizeof(struct gmac_rockchip_platdata),
 	.flags = DM_FLAG_ALLOC_PRIV_DMA,
 };