vpl: Add Kconfig options for VPL

Add VPL versions of commonly used Kconfig options.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/dts/Kconfig b/dts/Kconfig
index b19912d..f1d05cc 100644
--- a/dts/Kconfig
+++ b/dts/Kconfig
@@ -65,6 +65,15 @@
 	  which is not enough to support device tree. Enable this option to
 	  allow such boards to be supported by U-Boot TPL.
 
+config VPL_OF_CONTROL
+	bool "Enable run-time configuration via Device Tree in VPL"
+	depends on VPL && OF_CONTROL
+	default y if SPL_OF_CONTROL
+	help
+	  Some boards use device tree in U-Boot but only have 4KB of SRAM
+	  which is not enough to support device tree. Enable this option to
+	  allow such boards to be supported by U-Boot VPL.
+
 config OF_LIVE
 	bool "Enable use of a live tree"
 	depends on DM && OF_CONTROL
@@ -523,4 +532,12 @@
 
 endif
 
+config VPL_OF_REAL
+	def_bool y
+	help
+	  Indicates that a real devicetree is available which can be accessed
+	  at runtime. This means that dev_read_...() functions can be used to
+	  read data from the devicetree for each device. This is true if
+	  TPL_OF_CONTROL is enabled and not TPL_OF_PLATDATA
+
 endmenu