Backport new debian package patches from upstream v6.9 [REVPI-4067]

Command to list relevant commits:

$ git log --oneline v6.6..v6.9 -- scripts/package/ scripts/Makefile.package scripts/Makefile
1e3cd03c54b7 Merge tag 'loongarch-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
1d35aae78ffe Merge tag 'kbuild-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
097f1200bf7e kbuild: rpm-pkg: add dtb files in kernel rpm
cb8a2ef0848c LoongArch: Add ORC stack unwinder support
e2bad142bb3d kbuild: unexport abs_srctree and abs_objtree
fee9b6d14acd Revert "kbuild/mkspec: clean boot loader configuration on rpm removal"
435e86998edf Revert "kbuild/mkspec: support 'update-bootloader'-based systems"
bca17edb24cb kbuild: rpm-pkg: mark installed files in /boot as %ghost
615b3a3d2d41 kbuild: rpm-pkg: do not include depmod-generated files
f96beb84eff6 kbuild: deb-pkg: call more misc debhelper commands
1d7bae8f8c85 kbuild: deb-pkg: build binary-arch in parallel
caf400c8b68a kbuild: deb-pkg: make debian/rules quiet for 'make deb-pkg'
cc3df32c9f3a kbuild: deb-pkg: show verbose log for direct package builds
f82811e22b48 rust: Refactor the build target to allow the use of builtin targets
358de8b4f201 kbuild: rpm-pkg: simplify installkernel %post
6185d32170b6 kbuild: deb-pkg: use debian/<package> for tmpdir
1b5e94657320 kbuild: deb-pkg: move 'make headers' to build-arch
358c3f8cce6d kbuild: deb-pkg: do not search for 'scripts' directory under arch/
16c36f8864e3 kbuild: deb-pkg: use build ID instead of debug link for dbg package
5e73758b43c3 kbuild: deb-pkg: use more debhelper commands in builddeb
68e262f8017d kbuild: deb-pkg: remove unneeded '-f $srctree/Makefile' in debian/rules
eaf80f7f2c9c kbuild: deb-pkg: allow to run debian/rules from output directory
159956f34ede kbuild: deb-pkg: set DEB_* variables if debian/rules is directly executed
7d4f07d5cb71 kbuild: deb-pkg: squash scripts/package/deb-build-option to debian/rules
466e6fc43fb9 kbuild: deb-pkg: factor out common Make options in debian/rules
b88365b6d74e kbuild: deb-pkg: hard-code Build-Depends
9c65810cfb21 kbuild: deb-pkg: split debian/copyright from the mkdebian script
53243e098397 kbuild: deb-pkg: remove the fakeroot builds support
0df8e9708594 scripts: clean up IA-64 code
ef6609adf1ec kbuild: remove the last use of old cmd_src_tar rule in packaging
b28d6ca1c9cb kbuild: buildtar: always make modules_install
884f55f152cb kbuild: buildtar: Remove unused $dirs
259b8bd13db5 kbuild: deb-pkg: apply short -R and -j options
a55d4aee76ca kbuild: make binrpm-pkg always produce kernel-devel package
ffa46bbc5892 kbuild: rpm-pkg: generate kernel.spec in rpmbuild/SPECS/

Only those that are relevant to debian packaging have been backported.