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/include/remoteproc.h b/include/remoteproc.h
index 74d0172..089131f 100644
--- a/include/remoteproc.h
+++ b/include/remoteproc.h
@@ -34,7 +34,7 @@
  * @mem_type: one of 'enum rproc_mem_type'
  * @driver_plat_data: driver specific platform data that may be needed.
  *
- * This can be accessed with dev_get_uclass_platdata() for any UCLASS_REMOTEPROC
+ * This can be accessed with dev_get_uclass_plat() for any UCLASS_REMOTEPROC
  * device.
  *
  */