builddeb: make headers package thinner

Remove a bunch of files not used during external module builds:
 - foreign architecture headers
 - subtree Makefiles
 - Kconfig files
 - perl scripts

On amd64 system this looses a third of the resulting .deb size.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/package/builddeb

@@ -165,8 +165,8 @@ EOF
 done
 
 # Build kernel header package
-(cd $srctree; find . -name Makefile\* -o -name Kconfig\* -o -name \*.pl) > "$objtree/debian/hdrsrcfiles"
-(cd $srctree; find arch/*/include include scripts -type f -o -type l) >> "$objtree/debian/hdrsrcfiles"
+(cd $srctree; find . arch/$SRCARCH -maxdepth 1 -name Makefile\*) > "$objtree/debian/hdrsrcfiles"
+(cd $srctree; find include scripts -type f -o -type l) >> "$objtree/debian/hdrsrcfiles"
 (cd $srctree; find arch/$SRCARCH -name module.lds -o -name Kbuild.platforms -o -name Platform) >> "$objtree/debian/hdrsrcfiles"
 (cd $srctree; find $(find arch/$SRCARCH -name include -o -name scripts -type d) -type f) >> "$objtree/debian/hdrsrcfiles"
 if is_enabled CONFIG_STACK_VALIDATION; then