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/ddr/altera/sdram_agilex.c b/drivers/ddr/altera/sdram_agilex.c
index d6e7a17..497ff78 100644
--- a/drivers/ddr/altera/sdram_agilex.c
+++ b/drivers/ddr/altera/sdram_agilex.c
@@ -25,7 +25,7 @@
 
 int sdram_mmr_init_full(struct udevice *dev)
 {
-	struct altera_sdram_platdata *plat = dev->platdata;
+	struct altera_sdram_platdata *plat = dev->plat;
 	struct altera_sdram_priv *priv = dev_get_priv(dev);
 	u32 i;
 	int ret;