nir/peephole_select: don't special case nir_opt_collapse_if + limit = ~0

Not sure if this was intentionally left when block_check_for_allowed_instrs's
param was changed from bool to int, but it certainly was broken without the
previous commit for discards. Now those should work, so the (unintentional?)
special case can be removed.

Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33590>

src/compiler/nir/nir_opt_peephole_select.c

@@ -400,7 +400,7 @@ nir_opt_collapse_if(nir_if *if_stmt, nir_shader *shader, unsigned limit,
    /* check if the block before the nested if matches the requirements */
    nir_block *first = nir_if_first_then_block(parent_if);
    unsigned count = 0;
-   if (!block_check_for_allowed_instrs(first, &count, limit != 0,
+   if (!block_check_for_allowed_instrs(first, &count, limit,
                                        indirect_load_ok, expensive_alu_ok))
       return false;