mesa: fix _mesa_draw_nonzero_divisor_bits to return nonzero divisors

The bitmask is _EffEnabledNonZeroDivisor, so no need to invert it before
returning.

Fixes: fd6636ebc06d (st/mesa: simplify determination whether a draw needs min/max index)
Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Marek Olšák <maraeo@gmail.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4009>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4009>
1 file changed