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/mmc/mmc_write.c b/drivers/mmc/mmc_write.c
index 6a4453c..d23b7d9 100644
--- a/drivers/mmc/mmc_write.c
+++ b/drivers/mmc/mmc_write.c
@@ -73,7 +73,7 @@
 #endif
 {
 #if CONFIG_IS_ENABLED(BLK)
-	struct blk_desc *block_dev = dev_get_uclass_platdata(dev);
+	struct blk_desc *block_dev = dev_get_uclass_plat(dev);
 #endif
 	int dev_num = block_dev->devnum;
 	int err = 0;
@@ -193,7 +193,7 @@
 #endif
 {
 #if CONFIG_IS_ENABLED(BLK)
-	struct blk_desc *block_dev = dev_get_uclass_platdata(dev);
+	struct blk_desc *block_dev = dev_get_uclass_plat(dev);
 #endif
 	int dev_num = block_dev->devnum;
 	lbaint_t cur, blocks_todo = blkcnt;