For compute channel on gk20a, set lockboost size to zero. Bug 1573856 Change-Id: I369cebf72241e4017e7d380c82caff6014e42984 Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com> Reviewed-on: http://git-master/r/594843 GVS: Gerrit_Virtual_Submit