dm: core: Rename the priv/plat members

These are supposed to be private to driver model, not accessed by any code
outside. Add a trailing underscore to indicate this.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/core/uclass.c b/drivers/core/uclass.c
index e845f60..f60bc9a 100644
--- a/drivers/core/uclass.c
+++ b/drivers/core/uclass.c
@@ -165,12 +165,12 @@
 
 void *uclass_get_priv(const struct uclass *uc)
 {
-	return uc->priv;
+	return uc->priv_;
 }
 
 void uclass_set_priv(struct uclass *uc, void *priv)
 {
-	uc->priv = priv;
+	uc->priv_ = priv;
 }
 
 enum uclass_id uclass_get_by_name(const char *name)