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/bcm2835_sdhci.c b/drivers/mmc/bcm2835_sdhci.c
index 7beb3b5..958129c 100644
--- a/drivers/mmc/bcm2835_sdhci.c
+++ b/drivers/mmc/bcm2835_sdhci.c
@@ -251,6 +251,6 @@
 	.bind = bcm2835_sdhci_bind,
 	.probe = bcm2835_sdhci_probe,
 	.priv_auto	= sizeof(struct bcm2835_sdhci_host),
-	.platdata_auto	= sizeof(struct bcm2835_sdhci_plat),
+	.plat_auto	= sizeof(struct bcm2835_sdhci_plat),
 	.ops = &sdhci_ops,
 };