radeonsi: fix export count

Fixes: 17acff01a00 ("radeonsi: skip vs output optimizations for some outputs")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/2877
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4871>
1 file changed