binman: Allow configuration options to be used in .dts files

It is sometimes useful to be able to reference configuration options in a
device tree source file. Add the necessary includes so that this works.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>

scripts/Makefile.lib

@@ -168,6 +168,11 @@ ld_flags       = $(LDFLAGS) $(ldflags-y)
 dtc_cpp_flags  = -Wp,-MD,$(depfile).pre.tmp -nostdinc                    \
 		 -I$(srctree)/arch/$(ARCH)/dts                           \
 		 -I$(srctree)/arch/$(ARCH)/dts/include                   \
+		 -Iinclude                                               \
+		 -I$(srctree)/include                                    \
+		 -I$(srctree)/arch/$(ARCH)/include                       \
+		 -include $(srctree)/include/linux/kconfig.h             \
+		 -D__ASSEMBLY__                                          \
 		 -undef -D__DTS__
 
 # Finds the multi-part object the current object will be linked into