microsoft/compiler: properly handle failure in add_sysvalue

src/microsoft/compiler/nir_to_dxil.c

@@ -4258,9 +4258,13 @@ append_input_or_sysvalue(struct ntd_context *ctx, nir_shader *s,
          }
       }
    }
+
    ctx->system_value[sv_slot] = add_sysvalue(ctx, s, sv_slot, name, driver_location);
+   if (!ctx->system_value[sv_slot])
+      return false;
+
    exec_list_push_tail(&s->system_values, &ctx->system_value[sv_slot]->node);
-   return (ctx->system_value[sv_slot] != NULL);
+   return true;
 }
 
 struct sysvalue_name {