drm/amdgpu: Use instance table for sdma 4.4.2

For ASICs with sdma IP v4.4.2, add mapping for logical to physical
instances.

v2:
	Register accesses on bare metal should be based on physical
instance. Use GET_INST() to get physical instance.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Le Ma <Le.Ma@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>