Factor out the code for programming preloader handoff register values, the ISWGRP Handoff 0 and 1. These registers later control which bridges are enabled by the "bridge" command on Gen5 devices. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Chin Liang See <chin.liang.see@intel.com> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com> Cc: Tien Fong Chee <tien.fong.chee@intel.com>