target/loongarch: Support LoongArch32 DMW

LA32 uses a different encoding for CSR.DMW and a new direct mapping
mechanism.

Signed-off-by: Jiajie Chen <c@jia.je>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Song Gao <gaosong@loongson.cn>
Message-ID: <20230822032724.1353391-3-gaosong@loongson.cn>
Message-Id: <20230822071405.35386-3-philmd@linaro.org>
2 files changed