msm: kgsl: Don't set APRIV for A3xx GPUs

Targets with IOMMU-v1 uses privileged memory to switch
pagetable and APRIV is to allow the GPU to access privileged
memory. Currently none of the A3XX targets having IOMMU-v1
actually requires the APRIV to be set.

Inside adreno_set_apriv() function, ADRENO_REG_CP_CNTL register
is programmed which is not defined in oxili register spec for some
A3xx targets like 8916, 8909 etc. So calling adreno_set_apriv() for
A3xx targets should be avoided.

Change-Id: I991cf2735e9d403ce04cbd0581ed324cd87d242f
CRs-Fixed: 718275
Signed-off-by: Prabhat Awasthi <pawasthi@codeaurora.org>