Early makefile patching achieve 2 goals.
Firstly, avoid adding variables to each make call.
Secondly, it is later used by tools (e.g dkms) to build out-of-tree modules.

- Drop Xtables
- Drop MPLS
- Drop DCB
- Drop Openvswitch (because of MPLS requirement)
- Add IPv6 multicast support

- Backport fix about USB hub enumeration

This make it fail to boot.

- fix perms
- strip kernel and executables
- include all headers (e.g: missing vdso/const.h)
- provides VIRTUALBOX-GUEST-MODULES WIREGUARD-MODULE
- remove documentation
- remove sources broken symlinks
- remove sources lost objects

Security patches inside !

See: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20200602&id=9f984cacf4f4d53fd8a3f44d7f13528b81c1f6a8

Issue with iwlwifi.

See: https://www.phoronix.com/scan.php?page=news_item&px=Linux-5.6-Broken-Intel-IWLWIFI

./kernel/gen_kheaders.sh: line 77: cpio: command not found
make[1]: *** [kernel/Makefile:132: kernel/kheaders_data.tar.xz] Error 127
make: *** [Makefile:1071: kernel] Error 2
make: *** Waiting for unfinished jobs....