drm/msm/gpu: add per-process pagetables param

For now it always returns '0' (false), but once the iommu work is in
place to enable per-process pagetables we can update the value returned.

Userspace needs to know this to make an informed decision about exposing
KHR_robustness.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Jordan Crouse <jcrouse@codeaurora.org>

drivers/gpu/drm/msm/adreno/adreno_gpu.c

@@ -63,6 +63,9 @@ int adreno_get_param(struct msm_gpu *gpu, uint32_t param, uint64_t *value)
 	case MSM_PARAM_NR_RINGS:
 		*value = gpu->nr_rings;
 		return 0;
+	case MSM_PARAM_PP_PGTABLE:
+		*value = 0;
+		return 0;
 	default:
 		DBG("%s: invalid param: %u", gpu->name, param);
 		return -EINVAL;