Remove TARGET_PROJECT[_SYSTEM]_INCLUDES

Everything should be getting device specific kernel headers from the
device_kernel_headers header library these days.

This does change the behavior of system libraries on devices using the
VNDK -- they no longer get device-specific kernel headers by default, as
we generally expect the system image to be device-independent. The few
libraries that may still need this can use:

 LOCAL_HEADER_LIBRARIES += device_kernel_headers

Test: treehugger
Change-Id: I90ccb921d58b8d27dd0118a974202696e0af745f
diff --git a/core/soong_config.mk b/core/soong_config.mk
index cbc2dd1..aa20eeb 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -121,7 +121,7 @@
 $(call add_json_bool, ArtUseReadBarrier,                 $(call invert_bool,$(filter false,$(PRODUCT_ART_USE_READ_BARRIER))))
 $(call add_json_bool, Binder32bit,                       $(BINDER32BIT))
 $(call add_json_str,  BtConfigIncludeDir,                $(BOARD_BLUETOOTH_BDROID_BUILDCFG_INCLUDE_DIR))
-$(call add_json_list, DeviceKernelHeaders,               $(TARGET_PROJECT_SYSTEM_INCLUDES))
+$(call add_json_list, DeviceKernelHeaders,               $(TARGET_DEVICE_KERNEL_HEADERS) $(TARGET_BOARD_KERNEL_HEADERS) $(TARGET_PRODUCT_KERNEL_HEADERS))
 $(call add_json_bool, DevicePrefer32BitApps,             $(filter true,$(TARGET_PREFER_32_BIT_APPS)))
 $(call add_json_bool, DevicePrefer32BitExecutables,      $(filter true,$(TARGET_PREFER_32_BIT_EXECUTABLES)))
 $(call add_json_str,  DeviceVndkVersion,                 $(BOARD_VNDK_VERSION))