drm/amdgpu: Add register read/write debugfs support for AID's

SMN address is larger than 32 bits for registers on different AID's
Updating existing interface to support access to such registers.

Signed-off-by: Mangesh Gadre <Mangesh.Gadre@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Asad Kamal <asad.kamal@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>