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/mmc/ca_dw_mmc.c b/drivers/mmc/ca_dw_mmc.c
index 98d7f6b..f295c54 100644
--- a/drivers/mmc/ca_dw_mmc.c
+++ b/drivers/mmc/ca_dw_mmc.c
@@ -167,5 +167,5 @@
 	.ops		= &ca_dwmci_dm_ops,
 	.probe		= ca_dwmmc_probe,
 	.priv_auto	= sizeof(struct ca_dwmmc_priv_data),
-	.platdata_auto	= sizeof(struct ca_mmc_plat),
+	.plat_auto	= sizeof(struct ca_mmc_plat),
 };