util/inteltool: add inteltool path to include path

Add the inteltool path to the include path to be able to avoid ugly
include hacks like `#include "../inteltool.h"`.

Change-Id: Id363fa20fe3b52248a224ca14b2626a8e3ce44a2
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39744
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/util/inteltool/Makefile b/util/inteltool/Makefile
index 0a21c07..bc6bcb3 100644
--- a/util/inteltool/Makefile
+++ b/util/inteltool/Makefile
@@ -25,6 +25,7 @@
 CFLAGS  ?= -O2 -g -Wall -Wextra -Wmissing-prototypes
 LDFLAGS += -lpci -lz
 
+CPPFLAGS += -I$(top)/util/inteltool
 CPPFLAGS += -I$(top)/src/commonlib/include -I$(top)/src/commonlib/bsd/include
 CPPFLAGS += -I$(top)/src/arch/x86/include