fix: device_kernel_headers can't be found in the make world

Since device_kernel_headers is marked as 'vendor:true', it is exported
to the make world as device_kernel_headers.vendor. Use the correct name
with the .vendor suffix.

Bug: none
Test: BOARD_VNDK_VERSION=current m -j does not complain about
device_kernel_headers.

Change-Id: If3eaa3c5832820c914ef427668d70fa8d8d0bf97
diff --git a/core/binary.mk b/core/binary.mk
index 502f79e..10ce130 100644
--- a/core/binary.mk
+++ b/core/binary.mk
@@ -1375,7 +1375,7 @@
 import_includes := $(intermediates)/import_includes
 import_includes_deps := $(strip \
     $(if $(LOCAL_USE_VNDK),\
-      $(call intermediates-dir-for,HEADER_LIBRARIES,device_kernel_headers,$(my_kind),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/export_includes) \
+      $(call intermediates-dir-for,HEADER_LIBRARIES,device_kernel_headers.vendor,$(my_kind),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/export_includes) \
     $(foreach l, $(installed_shared_library_module_names), \
       $(call intermediates-dir-for,SHARED_LIBRARIES,$(l),$(my_kind),,$(LOCAL_2ND_ARCH_VAR_PREFIX),$(my_host_cross))/export_includes) \
     $(foreach l, $(my_static_libraries) $(my_whole_static_libraries), \