msm: kgsl: Hold the pm_qos vote at all times when ACTIVE

The GPU needs access to the L2 cache while running.  If the
CPU is not also active using the cache can lead to stability
issues.  Keep the CPU out of idle power collapse at all times
while the GPU is running.

CRs-Fixed: 397489
Change-Id: Iab2d8c601e903aadc4060f7c6d67bc128840edbf
Signed-off-by: Lucille Sylvester <lsylvest@codeaurora.org>