batmand: update to 2022-12-31 and simplify Makefile

batmand: update to 2022-12-31 and simplify Makefile

Patches:
- 0001-Allow-one-to-disable-forking-to-background-in-debug_.patch
is included in the upstream [1]

- 0002-batmand-Add-missing-string.h-include.patch
is included in the upstream [2]

Makefile is simplified, reordered to be able to move this package
to packages feed.

[1] https://git.open-mesh.org/batmand.git/commit/?id=2f62b17d4132f82c4716b672101eb7faa916192a
[2] https://git.open-mesh.org/batmand.git/commit/linux?id=aca79f595d20ed8ed5efa204c87f30174d5b4228

Signed-off-by: Josef Schlehofer <[email protected]>