added printk.cc to the sconsscript so it will actually build.
added printk.cc to the sconsscript so it will actually build.

SConscript:
    grrr, spent half an hour looking for why the linker was dying.  needed to include the new file printk.cc

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