While the AFSplitter code is currently used only by the luks module,
upcoming support for luks2 will add a second module that depends on it.
To avoid any linker errors when adding the code to both modules because
of duplicated symbols, this commit moves it into its own standalone
module afsplitter as a preparatory step.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>