The implementation of write_bootdata() and get_redirect_dir() was
copied verbatim in two different places, obviously a bad thing for
maintainability. This moves them to a new file multiboot.c as they
are only used for multiboot.
Change-Id: Id0279216e4dd019f8bf612a81d3835eff010e506
The idea is to share loading code between bootloaders and rolo().
Change-Id: I1656ed91946d7a05cb7c9fa7a16793c3c862a5cd
Reviewed-on: http://gerrit.rockbox.org/190
Reviewed-by: Marcin Bukat <marcin.bukat@gmail.com>