msm: clock-8960: set FORCE_PERIPH_ON in GFX3D_CC_REG

It appears that the timing parameters are not met for the wake
and sleep counters on some devices and forcing the 3d core memory
periphery to be on always is necessary to avoid the intermittent
GPU hangs when the gfx3d_ck is turned off and on.

Change-Id: Ia93498ed568a7962c9b4a30686bfb28673e9c559
CRs-Fixed: 320285
Signed-off-by: Tarun Karra <tkarra@codeaurora.org>
Signed-off-by: Jeremy Gebben <jgebben@codeaurora.org>