fdt: Drop use of non-existent OF_PLATDATA option

These are only present in SPL. Drop the references to non-SPL versions.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/dts/Kconfig b/dts/Kconfig
index bc5f220..44cc6bf 100644
--- a/dts/Kconfig
+++ b/dts/Kconfig
@@ -21,8 +21,8 @@
 
 config OF_CONTROL
 	bool "Run-time configuration via Device Tree"
-	select OF_LIBFDT if !OF_PLATDATA
-	select OF_REAL if !OF_PLATDATA
+	select OF_LIBFDT
+	select OF_REAL
 	help
 	  This feature provides for run-time configuration of U-Boot
 	  via a flattened device tree.