drm/amdgpu/sriov: Need to initialize the HDP_NONSURFACE_BAStE

it requires to initialize HDP_NONSURFACE_BASE, so as to avoid
using the value left by a previous VM under sriov scenario.

v2: it should not hurt baremetal, generalize it for both sriov
and baremetal

Signed-off-by: Emily Deng <Emily.Deng@amd.com>
Signed-off-by: Tiecheng Zhou <Tiecheng.Zhou@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>