gallium: remove unbind_trailing_count from set_vertex_buffers
What does this MR do and why?
gallium: remove unbind_trailing_count from set_vertex_buffers
It should implicitly unbind all bound buffers after "count".
This is a cleanup suggested by:
https://gitlab.freedesktop.org/mesa/mesa/-/issues/8142
Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io> (asahi & panfrost)