[csrng, dv] Fix csrng_intr_vseq bug for cs_hw_inst_exc interrupt test
[csrng, dv] Fix csrng_intr_vseq bug for cs_hw_inst_exc interrupt test

  - The "cmd_stage_ack_sts" was forced to a wrong value so that
    the cs_hw_inst_exc bug was not caught in the block verification

Signed-off-by: Muqing Liu <b1c0f8d5c8fd5df55dfdf439926eb15b5e395e02@wdc.com>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan