[simple_system] Add CSR to architecture extensions

Simple system uses CSR's and thus this is required.

Signed-off-by: Edward Kigwana <ekigwana@scires.com>

Author: ekigwana

examples/sw/simple_system/common/common.mk

@@ -8,7 +8,8 @@ COMMON_SRCS = $(wildcard $(COMMON_DIR)/*.c)
 INCS := -I$(COMMON_DIR)
 
 # ARCH = rv32im # to disable compressed instructions
-ARCH ?= rv32imc
+# ARCH ?= rv32imc # to disable control and status register access instructions
+ARCH ?= rv32imc_zicsr
 
 ifdef PROGRAM
 PROGRAM_C := $(PROGRAM).c