target/riscv: Reassign instructions to the Zbb-extension

target/riscv: Reassign instructions to the Zbb-extension

This reassigns the instructions that are part of Zbb into it, with the
notable exceptions of the instructions (rev8, zext.w and orc.b) that
changed due to gorci, grevi and pack not being part of Zb[abcs].

Signed-off-by: Philipp Tomsich <philipp.tomsich@vrull.eu>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Acked-by: Bin Meng <bmeng.cn@gmail.com>
Message-id: 20210911140016.834071-11-philipp.tomsich@vrull.eu
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>