drm/amd/display: add DCN32 to IP discovery table

[Why&How]
Add DCN32 to IP discovery to enable automatic initialization of AMDGPU
Display Manager

Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>