This implementation is no longer needed.

ffs is either a built-in function (for compilations with optimisation)
or taken from libiberty.a (which was added by the previous patch).

Cc: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>