drm/amdgpu: add amdgpu_device reference in ip block

To handle amdgpu_device reference for different GPUs
we add it's reference in each ip block which can be
used to differentiate between difference gpu devices.

Signed-off-by: Sunil Khatri <sunil.khatri@amd.com>
Suggested-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>