Makefile.lib: Re-use $(UBOOTINCLUDE) in dtc_cpp_flags

As in ASL case use same basic set of the inclusions.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index c14da10..2ff39d3 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -185,12 +185,10 @@
 
 # Modified for U-Boot
 dtc_cpp_flags  = -Wp,-MD,$(depfile).pre.tmp -nostdinc                    \
+		 $(UBOOTINCLUDE)                                         \
 		 -I$(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__