msm8974: defconfig: Turn on per process pagetable feature of graphics

Turn on per process pagetable feature of graphics for 8974 that
creates a separate graphics pagetable for every process using
the graphics core. This allows better security and separation of
address space of different processes.

Change-Id: I266fa6447b09a23833a36e41150e419aa6c394f4
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>