update swerv_wrapper LB density from 0.10 to 0.25

Signed-off-by: Augusto Berndt <augusto.berndt@precisioninno.com>

Author: gudeh

flow/designs/nangate45/swerv_wrapper/config.mk

@@ -28,7 +28,7 @@ export PLACE_PINS_ARGS = -exclude left:* -exclude right:* -exclude top:* -exclud
 export MACRO_PLACE_HALO = 10 10
 export MACRO_PLACE_CHANNEL = 20 20
 
-export PLACE_DENSITY_LB_ADDON = 0.10
+export PLACE_DENSITY_LB_ADDON = 0.25
 export TNS_END_PERCENT        = 100
 
 export FASTROUTE_TCL = $(DESIGN_HOME)/$(PLATFORM)/$(DESIGN_NAME)/fastroute.tcl