kbuild: do not include old-kbuild-file from Makefile.headersinst

Now asm-generic wrappers to be exported are all listed in
arch/*/include/uapi/asm/Kbuild.  "make headers_install" no longer
depends on any Kbuild files outside uapi directories.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

scripts/Makefile.headersinst

@@ -40,11 +40,6 @@ ifeq ($(skip-inst),)
 kbuild-file := $(srctree)/$(obj)/Kbuild
 -include $(kbuild-file)
 
-old-kbuild-file := $(srctree)/$(subst uapi/,,$(obj))/Kbuild
-ifneq ($(wildcard $(old-kbuild-file)),)
-include $(old-kbuild-file)
-endif
-
 installdir    := $(INSTALL_HDR_PATH)/$(dst)
 gendir        := $(objtree)/$(subst include/,include/generated/,$(obj))
 header-files  := $(notdir $(wildcard $(srcdir)/*.h))