target/riscv: update `decode_save_opc` to store extra word2

target/riscv: update `decode_save_opc` to store extra word2

Extra word 2 is stored during tcg compile and `decode_save_opc` needs
additional argument in order to pass the value. This will be used during
unwind to get extra information about instruction like how to massage
exceptions. Updated all callsites as well.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/594

Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20241008225010.1861630-16-debug@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>