dm: treewide: Rename ..._platdata variables to just ..._plat

Try to maintain some consistency between these variables by using _plat as
a suffix for them.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/usb/host/ehci-fsl.c b/drivers/usb/host/ehci-fsl.c
index dfeca89..8e79bdd 100644
--- a/drivers/usb/host/ehci-fsl.c
+++ b/drivers/usb/host/ehci-fsl.c
@@ -145,7 +145,7 @@
 	.probe = ehci_fsl_probe,
 	.remove = ehci_deregister,
 	.ops	= &ehci_usb_ops,
-	.plat_auto	= sizeof(struct usb_platdata),
+	.plat_auto	= sizeof(struct usb_plat),
 	.priv_auto	= sizeof(struct ehci_fsl_priv),
 	.flags	= DM_FLAG_ALLOC_PRIV_DMA,
 };