target/riscv: Reserve exception codes for sw-check and hw-err

target/riscv: Reserve exception codes for sw-check and hw-err

Based on the priv-1.13.0, add the exception codes for Software-check and
Hardware-error.

Signed-off-by: Fea.Wang <fea.wang@sifive.com>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240606135454.119186-6-fea.wang@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>