of: Move testcase FDT data into drivers/of

The testcase data is usable by any platform. This patch moves it into
the drivers/of directory so it can be included by any architecture.

Using the test cases requires manually adding #include <testcases.dtsi>
to the end of the boards .dtsi file and enabling CONFIG_OF_SELFTEST. Not
pretty though. A useful project would be to make the testcase code
easier to execute.
Signed-off-by: Grant Likely <grant.likely@linaro.org>

arch/arm/boot/dts/testcases/tests.dtsi

-/include/ "tests-phandle.dtsi"
-/include/ "tests-interrupts.dtsi"

arch/arm/boot/dts/versatile-pb.dts

-/include/ "versatile-ab.dts"
+#include <versatile-ab.dts>
 
 / {
 	model = "ARM Versatile PB";
@@ -47,4 +47,4 @@ mmc@b000 {
 	};
 };
 
-/include/ "testcases/tests.dtsi"
+#include <testcases.dtsi>

drivers/of/testcase-data/testcases.dtsi

+#include "tests-phandle.dtsi"
+#include "tests-interrupts.dtsi"

scripts/Makefile.lib

@@ -152,6 +152,7 @@ ld_flags       = $(LDFLAGS) $(ldflags-y)
 dtc_cpp_flags  = -Wp,-MD,$(depfile).pre.tmp -nostdinc                    \
 		 -I$(srctree)/arch/$(SRCARCH)/boot/dts                   \
 		 -I$(srctree)/arch/$(SRCARCH)/boot/dts/include           \
+		 -I$(srctree)/drivers/of/testcase-data                   \
 		 -undef -D__DTS__
 
 # Finds the multi-part object the current object will be linked into