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/ram/rockchip/sdram_rk3328.c b/drivers/ram/rockchip/sdram_rk3328.c
index 961c958..634fd41 100644
--- a/drivers/ram/rockchip/sdram_rk3328.c
+++ b/drivers/ram/rockchip/sdram_rk3328.c
@@ -617,6 +617,6 @@
 	.probe = rk3328_dmc_probe,
 	.priv_auto	= sizeof(struct dram_info),
 #ifdef CONFIG_TPL_BUILD
-	.platdata_auto	= sizeof(struct rockchip_dmc_plat),
+	.plat_auto	= sizeof(struct rockchip_dmc_plat),
 #endif
 };