panfrost: Enable PIPE_CAP_VERTEX_COLOR_UNCLAMPED
This tells Mesa to clamp vertex colours in the vertex shader. This improves rendering in a number of games such as Extreme Tux Racer and H-Craft Championships. Cc: 20.1 <mesa-stable@lists.freedesktop.org> Reviewed-by:Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com> Part-of: <mesa/mesa!5075>