anv: Fix UBO range detection in anv_nir_compute_push_layout
This fixes two bugs: First, if the same block index showed up twice, we
only pick the first one. Second, we weren't multiplying by 32. This
didn't show up in tests because RBA testing is garbage. Found while
looking at shaders from the UE4 Shooter demo.
Fixes: e03f9652 "anv: Bounds-check pushed UBOs when..."
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4578>