Fix the possibility of sleeping with locks held in sysctls by copying the

Fix the possibility of sleeping with locks held in sysctls by copying the
    data into temporary variables with the lock held then outputting to
    sysctls with the lock released. Rearranged a little extra code to aid
    this. Note that drm_memory_debug.h hasn't had this fix applied, but I
    consider that code to be just about dead anyway.