minor comments to decoder.isa
minor comments to decoder.isa

arch/mips/isa/decoder.isa:
    comments

andrewfu0325/gem5-aladdin,haowu4682/gem5,andrewfu0325/gem5-aladdin,haowu4682/gem5,haowu4682/gem5,LingxiaoJIA/gem5,andrewfu0325/gem5-aladdin,haowu4682/gem5,LingxiaoJIA/gem5,haowu4682/gem5,LingxiaoJIA/gem5,LingxiaoJIA/gem5,haowu4682/gem5,andrewfu0325/gem5-aladdin,haowu4682/gem5,haowu4682/gem5,andrewfu0325/gem5-aladdin,LingxiaoJIA/gem5,andrewfu0325/gem5-aladdin,haowu4682/gem5,LingxiaoJIA/gem5,andrewfu0325/gem5-aladdin,LingxiaoJIA/gem5