riscv32i-mock-sram: use PDN_TCL that we generally use in a BLOCKS scenario

Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>

Author: oharboe

flow/designs/asap7/riscv32i-mock-sram/fakeram7_256x32/config.mk

@@ -8,6 +8,10 @@ export SDC_FILE      = ./designs/$(PLATFORM)/riscv32i-mock-sram/fakeram7_256x32/
 export CORE_UTILIZATION = 50
 export CORE_ASPECT_RATIO = 8
 export PLACE_DENSITY = 0.80
+# fakeram7 doesn't block off M5, so limit to M4 here.
+# However, PDN will use M5, so it is still added to blockages.
 export MAX_ROUTING_LAYER = M4
 
 export PLACE_PINS_ARGS = -exclude left:* -exclude bottom:* -exclude top:* -min_distance 6 -min_distance_in_tracks
+
+export PDN_TCL                = $(FLOW_HOME)/platforms/asap7/openRoad/pdn/BLOCK_grid_strategy.tcl