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/video/sandbox_sdl.c b/drivers/video/sandbox_sdl.c
index 3e231e8..12edf9c 100644
--- a/drivers/video/sandbox_sdl.c
+++ b/drivers/video/sandbox_sdl.c
@@ -23,7 +23,7 @@
 
 static int sandbox_sdl_probe(struct udevice *dev)
 {
-	struct video_uc_platdata *uc_plat = dev_get_uclass_plat(dev);
+	struct video_uc_plat *uc_plat = dev_get_uclass_plat(dev);
 	struct sandbox_sdl_plat *plat = dev_get_plat(dev);
 	struct video_priv *uc_priv = dev_get_uclass_priv(dev);
 	struct sandbox_state *state = state_get_current();
@@ -49,7 +49,7 @@
 
 static int sandbox_sdl_bind(struct udevice *dev)
 {
-	struct video_uc_platdata *uc_plat = dev_get_uclass_plat(dev);
+	struct video_uc_plat *uc_plat = dev_get_uclass_plat(dev);
 	struct sandbox_sdl_plat *plat = dev_get_plat(dev);
 	int ret = 0;