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/rtc/i2c_rtc_emul.c b/drivers/rtc/i2c_rtc_emul.c
index 762769d..59043a7 100644
--- a/drivers/rtc/i2c_rtc_emul.c
+++ b/drivers/rtc/i2c_rtc_emul.c
@@ -231,6 +231,6 @@
 	.of_match	= sandbox_i2c_rtc_ids,
 	.bind		= sandbox_i2c_rtc_bind,
 	.priv_auto	= sizeof(struct sandbox_i2c_rtc),
-	.platdata_auto	= sizeof(struct sandbox_i2c_rtc_plat_data),
+	.plat_auto	= sizeof(struct sandbox_i2c_rtc_plat_data),
 	.ops		= &sandbox_i2c_rtc_emul_ops,
 };