kirkwood: fix calls to kirkwood_mpp_conf

With the new second save argument introduced by the previous patch, all
the calls to the function had to be fixed.

Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
cc: Holger Brunck <holger.brunck@keymile.com>
cc: Prafulla Wadaskar <prafulla@marvell.com>