kbuild: simplify scripts/headers_install.sh

Now that headers_install.sh is invoked per file, remove the for-loop
in the shell script.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/scripts/Makefile.headersinst b/scripts/Makefile.headersinst
index c96c4c2..d2b572a 100644
--- a/scripts/Makefile.headersinst
+++ b/scripts/Makefile.headersinst
@@ -58,7 +58,7 @@
 ifndef HDRCHECK
 
 quiet_cmd_install = HDRINST $@
-      cmd_install = $(CONFIG_SHELL) $(srctree)/scripts/headers_install.sh $(@D) $(<D) $(@F)
+      cmd_install = $(CONFIG_SHELL) $(srctree)/scripts/headers_install.sh $< $@
 
 $(src-headers): $(dst)/%.h: $(src)/%.h $(srctree)/scripts/headers_install.sh FORCE
 	$(call if_changed,install)