vpr: Don't disallow the timing-driven router with global RR graphs

Although it was previously called the NO_TIMING router it is really the
same code ans the timing-driven router.
diff --git a/vpr/src/base/CheckSetup.cpp b/vpr/src/base/CheckSetup.cpp
index 2dcfb6b..978fff4 100644
--- a/vpr/src/base/CheckSetup.cpp
+++ b/vpr/src/base/CheckSetup.cpp
@@ -23,12 +23,6 @@
     }
 
     if ((GLOBAL == RouterOpts.route_type)
-        && (TIMING_DRIVEN == RouterOpts.router_algorithm)) {
-        VPR_FATAL_ERROR(VPR_ERROR_OTHER,
-                        "The global router does not support timing-drvien routing.\n");
-    }
-
-    if ((GLOBAL == RouterOpts.route_type)
         && (BOUNDING_BOX_PLACE != PlacerOpts.place_algorithm)) {
         /* Works, but very weird.  Can't optimize timing well, since you're
          * not doing proper architecture delay modelling. */