radv: Fix variable name collision.

idx was aliased, and eb104e949ee4b7e0813d14f11a4a952bae48fe80 started
using the outer var in the inner scope ...

Fixes: eb104e949ee4b7e0813d14f11a4a952bae48fe80
Gitlab: https://gitlab.freedesktop.org/mesa/mesa/-/issues/3701
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7388>
1 file changed