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/imxrt_sdram.c b/drivers/ram/imxrt_sdram.c
index da5eb82..03d0d88 100644
--- a/drivers/ram/imxrt_sdram.c
+++ b/drivers/ram/imxrt_sdram.c
@@ -441,5 +441,5 @@
 	.ops = &imxrt_semc_ops,
 	.ofdata_to_platdata = imxrt_semc_ofdata_to_platdata,
 	.probe = imxrt_semc_probe,
-	.platdata_auto	= sizeof(struct imxrt_sdram_params),
+	.plat_auto	= sizeof(struct imxrt_sdram_params),
 };