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/max77686.c b/drivers/power/regulator/max77686.c
index 752dc88..f05d791 100644
--- a/drivers/power/regulator/max77686.c
+++ b/drivers/power/regulator/max77686.c
@@ -657,9 +657,9 @@
 
 static int max77686_ldo_probe(struct udevice *dev)
 {
-	struct dm_regulator_uclass_platdata *uc_pdata;
+	struct dm_regulator_uclass_plat *uc_pdata;
 
-	uc_pdata = dev_get_uclass_platdata(dev);
+	uc_pdata = dev_get_uclass_plat(dev);
 
 	uc_pdata->type = REGULATOR_TYPE_LDO;
 	uc_pdata->mode_count = max77686_ldo_modes(dev->driver_data,
@@ -721,9 +721,9 @@
 
 static int max77686_buck_probe(struct udevice *dev)
 {
-	struct dm_regulator_uclass_platdata *uc_pdata;
+	struct dm_regulator_uclass_plat *uc_pdata;
 
-	uc_pdata = dev_get_uclass_platdata(dev);
+	uc_pdata = dev_get_uclass_plat(dev);
 
 	uc_pdata->type = REGULATOR_TYPE_BUCK;
 	uc_pdata->mode_count = max77686_buck_modes(dev->driver_data,