nir/print: print io instr->name if available

this will always be more accurate than trying to find the name from
a variable

Acked-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28814>

src/compiler/nir/nir_print.c

@@ -1631,6 +1631,11 @@ print_intrinsic_instr(nir_intrinsic_instr *instr, print_state *state)
       return;
    }
 
+   if (instr->name) {
+      fprintf(fp, "  // %s", instr->name);
+      return;
+   }
+
    nir_foreach_variable_with_modes(var, state->shader, var_mode) {
       if (!var->name)
          continue;