spl: Allow enabling SPL_OF_REAL and SPL_OF_PLATDATA at the same time

Sandbox unit tests in U-Boot proper load a test device tree to have some
devices to work with. In order to do the same in SPL, we must enable
SPL_OF_REAL. However, we already have SPL_OF_PLATDATA enabled. When
generating platdata from a devicetree, it is expected that we will not need
devicetree access functions (even though SPL_OF_CONTROL is enabled). This
expectation does not hold for sandbox, so allow user control of
SPL_OF_REAL.

There are several places in the tree where conditions involving OF_PLATDATA
or OF_REAL no longer function correctly when both of these options can be
selected at the same time. Adjust these conditions accordingly.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/dts/Kconfig b/dts/Kconfig
index 9152f58..00c0aef 100644
--- a/dts/Kconfig
+++ b/dts/Kconfig
@@ -410,12 +410,14 @@
 	  declarations for each node. See of-plat.txt for more information.
 
 config SPL_OF_REAL
-	bool
+	bool "Support a real devicetree in SPL" if SANDBOX
+	depends on SPL_OF_CONTROL
+	select SPL_OF_LIBFDT
 	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
-	  SPL_OF_CONTROL is enabled and not SPL_OF_PLATDATA
+	  read data from the devicetree for each device. You do not need to
+	  enable this option if you have enabled SPL_OF_PLATDATA.
 
 if SPL_OF_PLATDATA