radeonsi: fix si_get_draw_start_count count value

Fixes: 0ce68852c1a ("radeonsi: implement multi_draw but supporting only 1 draw")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/3932
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8004>
(cherry picked from commit 5eda9673b2347aa33713790b3a04b8363862db2f)
2 files changed