drm/amdgpu: Add lsdma v7_0 ip block support

Add lsdma v7_0 ip block support.

Signed-off-by: Likun Gao <Likun.Gao@amd.com>
Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>