[Why&How]

Adds the firmware definition and missing cases statement
hooks for Beige Goby support in AMDGPU DM.
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>