radeonsi: use correct wave size in gfx10_ngg_calculate_subgroup_info
Fixes: 88efb63c ("radeonsi/gfx10: implement Wave32") Acked-by:Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com> Part-of: <mesa/mesa!6137> (cherry picked from commit b6fb09fd)