Update Makefile

Add PDK variable for simulation

Author: jeffdi

Makefile

@@ -26,6 +26,7 @@ export PDK_MAGIC_COMMIT=7d601628e4e05fd17fcb80c3552dacb64e9f6e7b
 export OPENLANE_TAG=2022.02.23_02.50.41
 export MISMATCHES_OK=1
 export PDKPATH?=$(PDK_ROOT)/sky130A
+export PDK?=sky130A
 
 # Install lite version of caravel, (1): caravel-lite, (0): caravel
 CARAVEL_LITE?=1
@@ -85,6 +86,7 @@ docker_run_verify=\
 		-e CARAVEL_ROOT=${CARAVEL_ROOT} \
 		-e TOOLS=/opt/riscv32i \
 		-e DESIGNS=$(TARGET_PATH) \
+		-e PDK=$(PDK) \
 		-e CORE_VERILOG_PATH=$(TARGET_PATH)/mgmt_core_wrapper/verilog \
 		-e GCC_PREFIX=riscv32-unknown-elf \
 		-e MCW_ROOT=$(MCW_ROOT) \