Revert "Revert "mako: msm: kgsl: Enable GDHS of GPU power rail while the screen is on""

This reverts commit a9fb5d44.

Underlying problem fixed by:

commit a31b7f3d
Author: Ajay Dudani <adudani@codeaurora.org>
Date:   Fri Aug 3 11:25:25 2012 -0600

    msm: kgsl: Hold pm_qos vote for active rendering

    Differentiate between the screen off case where kgsl shouldn't
    hold a pm_qos vote and the screen on case where power rails
    may be turned off after a long idle.  restore_slumber now
    corresponds to the screen on/off while strtstp_sleepwake covers
    the power rail collapse.

    CRs-Fixed: 386956
    Change-Id: Id4318f1aa87d6ad0653fe5db18c5d33bda1cc8bb
    Signed-off-by: Lucille Sylvester <lsylvest@codeaurora.org>
    Signed-off-by: Ajay Dudani <adudani@codeaurora.org>

Signed-off-by: Iliyan Malchev <malchev@google.com>