tcg/loongarch64: Import LSX instructions

Add opcodes and encoder functions for LSX.

Generated from
https://github.com/jiegec/loongarch-opcodes/tree/qemu-lsx

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Signed-off-by: Jiajie Chen <c@jia.je>
Acked-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230908022302.180442-2-c@jia.je>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>