i965: Don't bail on vertex element processing if we need draw params.

i965: Don't bail on vertex element processing if we need draw params.

BaseVertex, BaseInstance, DrawID, and some edge flag conditions need
vertex buffer and elements structs.  We can't bail early in this case.

Gen4-7 already do this properly.  Gen8+ did not.

Thanks to Ilia Mirkin for helping track this down.

Cc: mesa-stable@lists.freedesktop.org
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99144
Reported-by: Pierre-Eric Pelloux-Prayer <pelloux@gmail.com>
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>