Remove unnecessary functions.
Remove unnecessary functions.

cpu/exec_context.hh:
    Remove functions that shouldn't be accessible to anything outside of the CPU.

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