target/loongarch: Implement vld vst

This patch includes:
- VLD[X], VST[X];
- VLDREPL.{B/H/W/D};
- VSTELM.{B/H/W/D}.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Song Gao <gaosong@loongson.cn>
Message-Id: <20230504122810.4094787-42-gaosong@loongson.cn>
4 files changed