radeonsi: Always leave poly_offset in a valid state

This commit makes si_update_poly_offset set poly_offset to NULL if
uses_poly_offset is false. This way poly_offset either points into the
currently queued rasterizer, or it is NULL.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99451
Cc: "13.0 17.0" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
(cherry picked from commit d7d32b3bfe86bd89d94d59393907bce1cb9dab7c)
1 file changed