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/nexell_dw_mmc.c b/drivers/mmc/nexell_dw_mmc.c
index 680459b..d03d589 100644
--- a/drivers/mmc/nexell_dw_mmc.c
+++ b/drivers/mmc/nexell_dw_mmc.c
@@ -233,5 +233,5 @@
 	.bind		= nexell_dwmmc_bind,
 	.probe		= nexell_dwmmc_probe,
 	.priv_auto	= sizeof(struct nexell_dwmmc_priv),
-	.platdata_auto	= sizeof(struct nexell_mmc_plat),
+	.plat_auto	= sizeof(struct nexell_mmc_plat),
 };