drm/amdkfd: Use instance table for GFX 9.4.3

For GFX 9.4.3, use the logical to physical mapping table,
to get the correct XCD instance when accessing registers on
bare metal.

Signed-off-by: Mukul Joshi <mukul.joshi@amd.com>
Reviewed-by: Amber Lin <Amber.Lin@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>