kbuild: drop include2/ used for O=... builds

There is no longer any use of the include2/ directory.
The generated files has moved to include/generated.

Drop all references to said directory.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2 files changed