panfrost: enable DrawTransformFeedback*

This is needed for ARB_transform_feedback2, which I plan on requiring
for ES3. Also update docs/features.txt

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6247>
5 files changed