panfrost: Fix logic ops on Bifrost

opaque should not be set when logicops are enabled, that needs blending
even on Bifrost. Fixes is for when I believe the bug became possible to hit.
The logical error is older.

Fixes Piglit logicop tests again.

Fixes: d849d9779a7 ("panfrost: Avoid blend shader when not blending")
Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20685>
(cherry picked from commit 41d99c10d1f2dff160b732e5311da398eb1ed90a)
3 files changed