fix: overide TNS5 with TNS100

Signed-off-by: Harsh Vardhan <[email protected]>

Author: openroadie

flow/designs/nangate45/ibex/config.mk

@@ -49,4 +49,4 @@ export SDC_FILE      = ./designs/$(PLATFORM)/$(DESIGN_NICKNAME)/constraint.sdc
 
 export CORE_UTILIZATION ?= 50
 export PLACE_DENSITY_LB_ADDON = 0.20
-export TNS_END_PERCENT       ?= 100
+export TNS_END_PERCENT        = 100