target/loongarch: Implement vsll vsrl vsra vrotr

This patch includes:
- VSLL[I].{B/H/W/D};
- VSRL[I].{B/H/W/D};
- VSRA[I].{B/H/W/D};
- VROTR[I].{B/H/W/D}.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Song Gao <gaosong@loongson.cn>
Message-Id: <20230504122810.4094787-23-gaosong@loongson.cn>
3 files changed