mock-array: add comment about grt adjustment

Signed-off-by: Vitor Bandeira <[email protected]>

Author: vvbandeira

flow/designs/asap7/mock-array/fastroute.tcl

@@ -1,2 +1,3 @@
+# set custom layer ajustment to avoid congestion
 set_global_routing_layer_adjustment $env(MIN_ROUTING_LAYER)-$env(MAX_ROUTING_LAYER) 0.45
-set_routing_layers -signal $env(MIN_ROUTING_LAYER)-$env(MAX_ROUTING_LAYER)
+set_routing_layers -signal $env(MIN_ROUTING_LAYER)-$env(MAX_ROUTING_LAYER)