target/riscv: Reassign instructions to the Zba-extension

target/riscv: Reassign instructions to the Zba-extension

The following instructions are part of Zba:
 - add.uw (RV64 only)
 - sh[123]add (RV32 and RV64)
 - sh[123]add.uw (RV64-only)
 - slli.uw (RV64-only)

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: 20210911140016.834071-6-philipp.tomsich@vrull.eu
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>