core: the device/board/product kernel headers will be auto-generated

So, just add the output include directory to the include path

Change-Id: Ia370454237913a748288124f65a6b731b17d6e1a
Signed-off-by: Dima Zavin <dima@android.com>
diff --git a/core/config.mk b/core/config.mk
index dd15867..56ef97e 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -358,8 +358,7 @@
 
 HOST_PROJECT_INCLUDES:= $(SRC_HEADERS) $(SRC_HOST_HEADERS) $(HOST_OUT_HEADERS)
 TARGET_PROJECT_INCLUDES:= $(SRC_HEADERS) $(TARGET_OUT_HEADERS) \
-		$(TARGET_DEVICE_KERNEL_HEADERS) $(TARGET_BOARD_KERNEL_HEADERS) \
-		$(TARGET_PRODUCT_KERNEL_HEADERS)
+		$(TARGET_OUT_KERNEL_HEADERS)
 
 # Many host compilers don't support these flags, so we have to make
 # sure to only specify them for the target compilers checked in to