The allocator doesn't give us empty pages, so make sure that they're
full of zeros, just like the sysmem alloc path does.
Jira DNVGPU-16
Change-Id: I0ff8a0718829b13973535ba1111a8a11b91be04d
Signed-off-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-on: http://git-master/r/1178829
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Vijayakumar Subbu <vsubbu@nvidia.com>