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/power/regulator/act8846.c b/drivers/power/regulator/act8846.c
index 1783813..bdce973 100644
--- a/drivers/power/regulator/act8846.c
+++ b/drivers/power/regulator/act8846.c
@@ -128,10 +128,10 @@
 
 static int act8846_reg_probe(struct udevice *dev)
 {
-	struct dm_regulator_uclass_platdata *uc_pdata;
+	struct dm_regulator_uclass_plat *uc_pdata;
 	int reg = dev->driver_data;
 
-	uc_pdata = dev_get_uclass_platdata(dev);
+	uc_pdata = dev_get_uclass_plat(dev);
 
 	uc_pdata->type = reg <= 4 ? REGULATOR_TYPE_BUCK : REGULATOR_TYPE_LDO;
 	uc_pdata->mode_count = 0;