disas/riscv Fix ctzw disassemble

Due to typo in opcode list, ctzw is disassembled as clzw instruction.

Signed-off-by: Ivan Klokov <ivan.klokov@syntacore.com>
Fixes: 02c1b569 ("disas/riscv: Add Zb[abcs] instructions")
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-ID: <20230217151459.54649-1-ivan.klokov@syntacore.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>