kbuild: install all headers when arch is changed

We see some header files that are selected dependent on
the actual architecture so force a reinstallation
of all header files when the arch changes.
This slows down "make headers_check_all" but then
we better reflect reality.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

scripts/Makefile.headersinst

@@ -43,9 +43,10 @@ printdir = $(patsubst $(INSTALL_HDR_PATH)/%/,%,$(dir $@))
 
 quiet_cmd_install = INSTALL $(printdir) ($(words $(all-files))\
                             file$(if $(word 2, $(all-files)),s))
-      cmd_install = $(PERL) $< $(srctree)/$(obj) $(install) $(header-y); \
-                    $(PERL) $< $(objtree)/$(obj) $(install) $(objhdr-y); \
-	            touch $@
+      cmd_install = \
+        $(PERL) $< $(srctree)/$(obj) $(install) $(SRCARCH) $(header-y); \
+        $(PERL) $< $(objtree)/$(obj) $(install) $(SRCARCH) $(objhdr-y); \
+        touch $@
 
 quiet_cmd_remove = REMOVE  $(unwanted)
       cmd_remove = rm -f $(unwanted-file)